Groves’ Congealed Fir Varnish

                             For oil painting in a traditional and perfectly lasting manner. 

Above image: Congealed Fir Varnish AKA "Fir Wax". Looks exactly like a soft beeswax .... but it isn't.

The Search for Rubens' Painting Medium; Painting with Solvents via the use of Resinous Varnish with Oil Paint

In his 1948 book, "Secret Formulas and Techniques of The Masters", Jacques Maroger made claim that a "mastic jelly" created by the mixture of a leaded drying oil with spirit mastic varnish was a major part of Rubens' long-lost painting medium.* He also observed the master's paint, characterizing it as often oddly granular in appearance. Maroger reasoned this granularity was likely due to its containing wax-paste. [* Maroger combined the 1830 guesswork of J.F.L Merimee regarding Rubens' supposed use of a thick "jelly" (constructed from cooked lead paste and spirit mastic varnish) with a falsely-attributed passage from Max Doerner maintaining VanDyck's use of leaded-oil and spirit mastic varnish as a "white jelly" medium for his colors (essentially a form of megilp).]

Many followers of Maroger remain convinced to this day that mastic jelly, with or without wax, is indeed the basis of Rubens' painting medium. Unfortunately, as far as I have learned, no mastic or wax has ever been found in any Rubens' paint chip, though his paint quite often does betray the presence of pinene. This is rather bad news for Maroger because the construction of leaded mastic jelly (AKA his "Rubens' Jelly") does not require heating the mastic resin anywhere near hot enough to destroy this resin's inherent chemical "markers". In fact, spirit mastic varnish is often made without heating, at all. As for wax, that can also be readily-combined in oils and solvents via either a gentle heat or a 'cold' mechanical maceration. As little or no heating is required, wax or mastic 'fingerprints' should easily still betray their presence within the old paint chips-- that is, if they are truly involved in Rubens' paint; and yet, nada is yet found. Some believers claim the reason for this failure to ID any mastic or wax is due to the oil, resin, and possible wax somehow cross-linking over the years to create a completely different material. Perhaps, I don't know... but if true, then one must wonder why there is the finding of pinene? Wouldn't a coniferous-type pinene-resin cross-link, too? Again, I don't know.

These questions generate another group of today whose members claim Rubens never used resin varnishes, nor any resinous medium at all; and that his painting medium was nothing more than simple oil -- alone or with turpentine spirit -- or variously cooked or sunned combinations thereof. They say Rubens painted in a fairly 'straight-forward' manner with very basic materials. This group sees nothing unusual about Rubens' paint beyond what great talent can produce....and they pretty much base their suppositions upon modern day science's failure to find much of anything excepting oil and "a little pine resin" within R's paint. [Some maintain the 'pine resin' finding might be simply a trace left from Rubens' use of turpentine-spirit. I would doubt this, though, as findings of "a little pine resin" would explode rampantly among the paint chips of too many Golden-Age masters who also used that commonly-available spirit.]

Allow me to somewhat enter the fray with another possibility; but first, though, some thoughts about fools and foolishness. Seeking knowledge is not, in itself, foolish, though a seeker can easily become a fool. Like too many others out there, past and present, I have studied Rubens' work with intensity and performed far too many trials in re-creating his effects. I recognize others lay claim to his method, and I'm fine with that; though I must point out one insurmountable difficulty in our quest: Only Rubens knew what his method and medium were; and he will not reveal either. This remarkable painter left us some written clues, yes, but he never actually said what he used.

For noteworthy regards, Rubens did say he approved of sun-treated and leaded-drying oil. He mentioned using a solvent while painting and told Mayerne (who was sitting for his own portrait at the time) that he preferred turpentine spirit over spike oil. He also informed Mayerne that he added varnish to his paint*. Rubens referred to this varnish as the "hard varnish" (the adjective "hard" utilized likely in the sense of "firm", rather than our more modern classification of 'hard' or 'soft' resin-derived varnish-- which could mean Rubens' varnish was a firm consistance (or perhaps even congealed?). According to his own quoted words, Rubens possessed at least some rather intimate knowledge about Larch balsam and Silver Fir balsam. He also warned that his own oil paintings kept in darkness would sallow due to the oil-ingredient. Finally, and based upon at least one letter he wrote, Rubens was quick at painting-completion, and some of his canvas-works could be afterwards shipped rolled in a matter of days. [*Note: Rubens' contemporary critics maintained that he painted with too much varnish and that his paintings would not outlast him.]

We might also gain clues by closely looking at Rubens' actual paint; and after all, this man's paint has lasted well and has pretty much come down to us in a close-to-original condition-- and this may be stated apriori when one reviews the many historical visual descripts written and uttered over and about Rubens masterworks as they appeared through the dimension of time. To wit: Rubens generally painted thinly and made great use of transparent and translucent paint. Contrary to the words of some, Rubens' paint possesses a certain distinct character. For one, there are often found passages which seem performed by means of a thixotropic painting jelly -- hence the many current believers in Rubens' possible use of wax or a mastic jelly like megilp. Building on this thixotropic paint-appearance, Rubens somehow managed to utilize asphaltum in a way where it kept its place and could even be used as an underpaint. That, in itself, is rather astounding! More later, though. A third noteworthy mention comes from Maroger, who, we should note, was once chief conservator at the Louvre. Maroger had perfect and repeated opportunity to closely examine Rubens and many other master's paint. Curiously, Maroger often observed that aforementioned oddy "granulated" effect which sometimes occurred within all of Rubens' colors. Maroger decided this granular effect was not due to poor grinding of the colors*; thus he pronounced a wax paste as being involved in Rubens' paint. [* From Maroger's 1948 book, chapter concerning Rubens, pages 94-95: "All the pigments, whether in the impasto or in the glazes, are of a semi-translucent material and present the appearance of a rich mousse. The general tone of the paintings is suggestive of amber, but the most banal colors are seen to take on a precious, almost pearly quality. The glazes, even the most liquid, have remained where they were placed, without running. There are always to be found in this material very apparent granulations, whatever the pigment employed. These were due to the wax and cannot be attributed to poor grinding of the colors, for the masters were very careful about the quality of their materials, whether their paintings were executed by themselves or by their pupils." Additional note: Maroger also found a similar granulated appearance in Titian's and Tintoretto's paint-- thus making claim they, too, used wax.]

Well, that's about it for the historical and visual information concerning Rubens and his paint; and it is only a meager base to build upon. Accordingly, I make herein no claim to having uncovered "Rubens Jelly", or whatever. I only offer a possibility; and so I shall venture to the cliff-edge gladly but I will not jump over it. So declaring, I'll now share a plausible theory concerning Rubens' method and material with you right up front:

Peter P. Rubens began with lean oil paint-- generally nut oil rubbed-up with pigment-- then he added a good dose of some sort of thixotropic varnish to this paint. This varnish effectively congealed the lean oil paint while also making that paint more transparent or translucent. He may have kept this tempered oil paint all ready to go by storing it within bladders; or he may have worked the varnish into his lean ground paint just prior to use; and at which time, he mixed into the tempered varnish-and-oil paint a requisite amount of either oil of spike or, his preferred solvent, turpentine spirit; afterwards, he proceded to paint with this solvent as his only medium throughout the work session. As to the mysterious varnish -- the varnish that made his paint behave in similar to a jelly or wax medium -- I believe that varnish was very likely based on either fir resin, or a combination of fir and some other related pinene-bearing resin.

Fir Resin "Wax"

Beginning in the later ninties, I uncoved the means for making jelly-like varnishes and mediums based upon pinene-bearing resins. I term these resins "S-P-F" resins. As with lumber yard two-by-fours, S-P-F simply denotes Spruce, Pine, Fir. I should point out that any and all of these spruce-pine-fir balsam/resins will almost certainly produce a finding of pinene, easily matching the finding of "a little pine resin" noted in so many modern-day paint analyses of Rubens' paint-chips. Interestingly, many of these S-P-F trees produce good and durable lightly-colored resins which can be utilized to make jelly mediums-- mediums quite similar in appearance and performance to mastic-based jelly mediums. Of course, these S-P-F resins were historically readily-available to craftsmen in Europe and other realms. Now, you won't find this shared information anywhere else, in book or website venue; yet these "jellies" exist and I have been working with them for more than a decade. I have been reluctant to offer these S-P-F type jellies only because I originally felt they might produce soft oil paint; however, today, after these many years of testing, I am assured this is not the case.

"Fir Wax" is my pet name for one of these S-P-F gels. As its name implies, Fir Wax is a concentrated congealed fir-based oil varnish. Fir Wax looks and behaves much like true wax; except it dries quickly to a very tough and durable film; plus it is glossy whereas wax produces a dull soft finish. This oddly-congealed varnish is composed of fir resin, walnut oil, and a traditional solvent. This varnish toughens oil paint much more than fir balsam; plus it engenders faster-drying. Fir Wax contains no gelling substances besides the fir resin, itself. What I mean is, there are no gelling-agents such as aluminum stearate, wax, bentonite; neither are there oily paint-darkening bulking agents such as fumed silica, chalk, barytes, kaolin, etc.

The congealed condition of this particular varnish allows it to perform in many valuable functions. It behaves like a stabilizer in oil paint. It can be thinned with oil or solvent to create soft jelly mediums or wood coatings. I am of the opinion that Fir Wax works well with a system of oil painting using solvents and in a manner quite like egg tempera, whereby Fir Wax is substituted for the egg-component, and a chosen solvent takes the place of the water. I believe this solvent-based and tempera-like oil painting technique was likely discovered by the Van Eycks and later used by Rubens and many other Northern and Southern painters. Again, I cannot claim with certainty that it was their wonderous methodology, but I believe it so.

I should offer some basic standards here: A tempera-like oil painting methodology can work rather well if the right varnish is used to boost the binding power of the oil. Additionally, if the varnish can also congeal the paint, more solvent can be then incorporated into the paint and without fear of running or diffusion. Thin lines may be painted in an ink-like manner. Colors keep their place beautifully, and even the troublesome asphaltum will behave. Plus, no extra oil is ever required; only a solvent. This means colors do not yellow or darken with age, as happens when the oil constituent in the paint increases. With this solvent-application method, the paint remains lean of oil. [Note: Fir Wax transparentizes paint without the addition of yellowing oil-bulking agents such as fumed silica, aluminum stearate, chalk, kaolin, or barytes. Every one of these oil-bulking agents can allow a certain transparence/translucense to oil paint; unfortunately, each agent also greatly increases the oil-content of the paint, which will eventually cause paintings to become quite yellow and lower in tone.]

Fir Balsam?

Various lightly-colored unctuous Fir balsams such as Strasbourg Turpentine or the balsam of the European White Fir have a long history of use in oil painting. Writings tell us fir balsam was known and used to create excellent durable varnishes by Italian masters of the 1500's, such as Correggio. It was likely used by Leonardo, too. Fir was also prescribed as a painting varnish by Armenini (1587), who gave recipe compounding the fir with naphtha, and directing it be mixed with all the colors and at all stages of paintng. As a spirit varnish, fir was early on considered the supreme final coating for oil paintings. I maintain a strong hunch the Venetian Painters, as well as Peter P. Rubens, made use of fir balsam, in some form -- perhaps even the unusual form we now offer, which is a congealed fast-drying fir oil varnish.

Now, in its simple basic form, fir balsam offers some welcome benefits, though it is not perfect. For instance, the honey-like substance can increase gloss amazingly, but the balsam often sets up the following conditions: soft easily-dissolved paint-film*; creeping/running, diffusion/leveling on drying; long-remaining tackiness/stickiness; or the balsam may often fall out of suspension when mixed with thickened oils. Painters of today usually thin fir balsam with turps or spike but this does nothing to improve hardness and durability. Some mix the balsam with stronger agents, such as stand oil or a hard varnish. I believe there is merit in this approach as it provides the positives while diminishing the negatives of the balsam. [*The aforementioned Max Doerner was an early 20th C. advocate promoting balsams combined with oil paint to re-create the technique of the olden masters. His book is filled with such advice. Doerner's students carried forth his claims and all seemed pretty much positive until Helmut Ruhemann of the National Gallery performed 30-year-later cleaning trails on some of the students likely balsam-made works. Ruhemann wrote that he found discolored and soft easily-dissolved paint, which is something old master paint is generally not known for; on the contrary, OM paint -- especially that of the Northern masters-- is typically found to be extremely hard and resistant to solvent-attack. Ruhemann's findings might not be surprising when we realize that balsams, especially larch balsam (AKA Venetian turpentine), serve as plasticizers in paints and varnishes. Perhaps the lapse of thirty years is not sufficient time to allow curing of balsam-laden paint ...though that particular soft-keeping trait holds no appeal to myself. I should add that the inclusion of wax and mastic might have had a dirty hand in Ruhemann's claim; and of course, we who actually paint should necessarily take some heed against blindly accepting the words of any conservator, who like ourselves, is merely human, after all.]

Use of the Fir Wax with Solvents

As a congealed varnish, Fir Wax may be thinned-down with a solvent of choice then easily brushed-out or rubbed-out with the hand or cloth onto any surface, such as an oil painting or a violin, where it will function as a glossy filling coat that retains that gloss and can be set firmly within fifteen minutes or less; and fully dry within 24 hours. It possesses wear and water-resistance, produces an excellent longevity; and without any fear of running or spreading once placed.

When this Fir Wax is mixed with simple oil-and-pigment paint, the effect is also very much like adding a thick wax paste. The paint stands up and stiffens considerably more than wax, though. The applied oil paint sets firmly and can then be gently worked over again and again. Upon total paint-drying -- 48 hours or so-- the completed work will exhibit a fine gloss and require no further varnishing later on. Again, numerous solvent-thinned layers can be applied one-atop-the next by the use of this congealed fir varnish. As mentioned, this technique resembles egg tempera, though without the egg and water.

Now, very important, if you cannot or will not paint with solvents, this tempera-like method is not for you. If you wish to use an all-oil technique, you can add 25-30% drying oil to this varnish and create a medium similar to megilp; then use that as you would with regular oil-only paint-- but I am firm in my belief that the majority of olden oil painters --if they used this sort of congealed varnish-- used it in conjunction with a solvent, such as lavender, rosemary, naphtha, spike, or turpentine spirit. Solvents can be dangerous to health. OK, if you can tolerate solvents then do read on.

Expanding here, this unique varnish performs exceptionally well with a certain novel painting methodology, one which I believe was first introduced by the brothers Van Eyck. The technique depends heavily on the use of a solvent. You see, whenever regular oil paints are mixed with this fir "jelly", they may then be applied in a pseudo-tempera-like fashion, thinning the paint as you work to any desired consistency via dipping the brush in a solvent, such as turpentine, spike oil, lavender essence, or, the least desirable, common mineral spirits.

Paint compounded with this Fir Wax can then be thinned-down with pure solvent to the consistence of tempera (or watercolor) and still keep its place; and with great resistance against running or spreading.

Due to the solvent-use, brushing-facility is extreme. A loaded brush can create a stroke that can travel effortlessly for several feet across a dry and sealed priming before recharging. Thicker opaque paint rolls off the brush with an equally-effortless flourish, creating juicy highlights where desired.

As earlier noted, I have been personally testing this material off-and-on within my own paintings since the nineties. The paintings produced have remained clean and bright and the paint is exceedingly tough against solvency; much tougher than were I to have used any of the common balsams historically available. Fir balsam is very expensive but well-worth the cost for its use in oil painting craft.

Basic Oil Painting with Solvent: Problematic by Design

If I might back-up a bit here, it is well-known and long-known that you can 'oil paint' with some added solvent, say turpentine spirit, by simply mixing that spirit with your basic pigment-and-oil paint upon the palette, and then putting the brush to the canvas or panel. It is also well-known that you cannot add very much solvent to your paint, or else that paint will more-resemble powder than a cohesive paint-film. Fact is, a bit too much solvent and you will be able to rub the dried film off the surface with your finger. This is because oil mixed with more than a scant amount of solvent becomes compromised; it forms a weakly-bound material due to the oil being extended by the solvent. There is also a physical mechanic involved with this operation: The solvent soon evaporates from above the pigments while driving the now-weakened oil beneath. By this mechanic, the pigment becomes relatively 'dry', which means the final dried paint-layer is powdery and crumbly, as it is not thoroughly surrounded or encapsulated by the weakened binding oil.

If you add some resinous varnish to your paint then you can add much more solvent without reducing the latent binding-power. A decent resin varnish is not noticeably harmed by a solvent-addition. Resin varnish behaves like a good friend to both oils and solvents. The three ingredients simply behave better and remain better together. Certain proper resin varnishes will intermix with and carry the oil to the surface along with the evaporating solvent; thus effectively leaving the pigment properly encapsulated. The resulting paint will be durable and remain colorful.

Still, even with the resinous varnish added, the improved thinned-down oil paint may likely run and sag. In other words, the paint will not 'keep its place'. Also, though solvent flash causes a certain amount of "set" to the stiffening paint, this set may not allow any overpaint while wet. And so, even if you are using a proper and durable varnish you may yet have a paint behavioral problem .

A congealing varnish can 'solve' this malady by providing an increased 'set', or resistance to the paint after solvent-flash.

Sample Demo, Using Rubens’ Method ..... and Asphaltum

Aside from those traits already noted, the use of this congealed Fir Wax varnish with a solvent offers some additional attributes. For one, it allows a rapid paint-application; second, it fully supports the use of various known-to-be-faulty oil paints, such as carmine and verdigris, paints which cannot last in oil, alone, and must be bound with a pinene-type varnish, such to allow application with safety and durability. For another instance, consider the notorious true asphaltum, which I must necessarily mention because Rubens did often use it within his own lasting work.

It is known that the 1600's Dutch and other early painters were seduced by the beautiful but wicked asphaltum; and yet their work does not suffer any consequences, even when the asphaltum was used in the underpainting! This particular congealed fir varnish allows such use.

This closeup shows the lovely transparent color available to this fossil brown, that is, when you can tame it!

Asphaltum is a naturally-occurring glassy resinous mineral found in seams. It crushes to a powder but must be melted into oils and spirits to create its best attributes. Asphaltum has been used in oil painting since at least the 1500's.

Asphaltum presents a perplexing dilemma. When thinned-down, this so-called bituminous material produces the most wonderfully-glowing and transparent golden-brown color; and when applied in its opaque top-color form, it shows off an intense 'burning' blackness. Also, when this weak-tinting brown is reduced by a slight bit of white, it becomes a pearly grey that goes well with flesh, clouds, tree-trunks, and so on. Asphaltum's weak-tinting attribute produces only a minor sombering effect when it's mixed with other colors; and so it can be used as an initial underpaint for skies, etc, where another brown might wreck havoc with superimposed coloring.

Yes, color-wise, asphaltum is perhaps the most exquisite brown ever found. Yet, when the raw material is ground (or more aptly 'melted') into oil it but barely solidifies, never actually becoming hard. Simply combined in oil, this brown goop will not keep its place on the palette, let alone the panel or canvas. It slumps and behaves like a thick eventually-firming though never-quite-drying varnish, which is exactly what it is. Asphaltum is a mysterious glassy resinous geologic matter that generally melts easily into hot oils and solvents; but, again, in oil, even drying oil, it seems never to fully harden, allowing it to creep and fissure on warm days. Moran, Cole, Church, Bougie, and too many other 19th C. painters loved the stuff. They 'got away' using it only as a glaze layer supported by an overpowering varnish-carrier. By comparison, Rubens was able to use this brown in his underpainting; and his phenomenal performance has been puzzling we moderns for nearly four centuries.

Now, some 19th C. history-searchers maintained the amazing performance of the earlier asphaltum was due to it being conjured from a certain Middle Eastern bitumin, one that is so hard that it out-performs all others. Well, that could be. I've never tried that version -- and no supplier today seems able to obtain it. Gilsonite from Utah is the only type I've tried. Gilsonite is so 'fossilized' that you need a bit of heat to combine the crushed glassy black-ish resin with a solvent. That's quite decent; and if asphaltum conjured from Gilsonite still creeps around on the palette -- and it does-- then I simply cannot imagine anything behaving any better.

The early 19th Century painter/researcher J.F.L.Merimee was aware of the true asphaltum's intractible nature. He wrote in his 1830 book, "The Painter in Oil..."(page 33): "...asphaltum, which, whether it be dissolved in drying oil or oil of turpentine, is equally clammy and intractable, for it is impossible to keep it on the palette, or yet to spread it sufficiently thin upon any part of the picture, without its running beyond the bounds required." Merimee then passed along a recipe for creating artist's asphaltum oil paint which involved much wax and mastic within the paint-mix.

True enough, ample wax and mastic will engender a paste-like consistence and seemingly keep the lovely golden-brown creature from spreading on the palette; but it will not in any way stop the future degradation of the paint. Again, adding lean copal or amber, or lean sandarac will make it much better and even allow it a use for amazing glazing effects.... but that's it. You would best forget about using this asphaltum within the underpainting. It is akin to painting on never-drying plastic gook. Most every other oil paint eventually becomes rigid; but asphaltum-in-oil may remain 'plastic' for too many years, stowing havoc upon whatever paint resides above it....and, repeating myself, wax will do anything but help in the final matter.

Merimee also came up with a painting method for asphaltum-- a method he claimed made the conjured brown "behave in the manner of Rubens". He mixed lead paste ("oglio cotto", which is nut oil gently cooked with half its quantity of lead carbonate until the whole becomes a clear paste) with strong mastic varnish to create a substance he described as a pomade-like painting varnish. Thus he wrote, ".... when mixed with this varnish, that tendency (of asphaltum to spread and dry too slowly) is prevented, and it becomes as manageable as the other colours."

Making it behave...

My point in mentioning all this background is that the nefarious asphaltum can be tamed. According to my own trials, this nasty but beautiful and seductive color can be applied easily and without further consideration by use of the Fir Wax. It will actually be firm enough to paint over in a matter of minutes, endowing the wicked paint with a wonderful attribute towards laying in the preliminary sketch; which is precisely what Rubens used it for.

Now, I'll state up front that I did find some success by Merimee's "pomade" route, that is when I used basic Gilsonite conjured with a solvent and without any oil. Indeed, the mastic-and-lead paste combo gave the solvent-based asphaltum some needed 'backbone', allowing its use in a manner visually similar to Rubens' approach.

Still, the Merimee pomade's performance was less than stellar... and, it should be worth mentioning again, one must wonder why there is no chemical 'footprint' of mastic in Rubens' paint...?

As a visual comparison, the following image shows Gilsonite asphaltum dissolved in turps; and then-- at time of use-- combined in equal amounts with (1) Fir Wax (2) Megilp (3) our own Gelling Copal Varnish mixed 1:1 with nut oil, and (4) Merimee's lead paste combined with mastic varnish 'pomade'.

The asphaltum mixed with Fir Wax retained the brush-hatchings exactly and was solidified enough to paint over in 15 minutes. The second sample created with megilp (Maroger's Rubens' jelly but w/o wax) looked softened from the get-go. It remained wet and refused to solidify for four days, which allowed the brush-hatchings to completely diffuse. The third sample created with Gelling Copal Varnish kept the brush-hatching rather well, too, though it could not be overpainted until it was dry-- about 24 hours. The fourth sample made using Merimee's lead paste and mastic varnish pomade produced soft hatchings but was capable of being painted over in fifteen minutes-- all-in-all, not so bad.

Making Asphaltum

Having made asphaltum in too many different ways, I can supply some small guidance in its creation: First, don't make it as Merimee prescribes by adding wax* and mastic. Also, do not melt your crushed asphaltum into leaded drying oil, or any siccative or raw oil, for that matter. Do not, as some advise, burn your asphaltum to a cinder; then re-grind that residue into a drying oil -- that approach destroys the glowing wonder of the color. In such case, you should just as well skip it altogether and use burnt umber, instead. [*Note: Wax is an oil-bulking and paint-softening agent within oil paint or painting mediums. If you must use it, keep it to a very minimum to achieve your intended effect. True, great oil painters since the 1700's have added wax to their colors to make them behave in similar manner to the old masters; however, Eastlake accurately informs the careful reader there was never uncovered any written evidence whatsoever maintaining the old masters using wax in their craft of oil painting.]

The very best method for making asphaltum, such that it shall exhibit all its charms yet serve you without fear of change, is to gently heat it with an amount of solvent in a boiling water bath. Keep the oil out of it! Still, and as Merimee points out, using the solvent, alone, will not stop it from moving, spreading on the painting or palette. Something more must be compounded with it at the time of actual painting to procure its best use. That's where a proper medium comes in; and so again I must maintain a strong belief that Rubens' medium or varnish-- whatever it was-- performed admirably when used to temper his own asphaltum for use in the preliminary sketch. [Groves' recipe for making spirit asphaltum: Place 1 tbls. powdered Gilsonite and 1-1/2 tbs. turpentine spirit into a clean baby-food type jar. Place the jar in a roiling (not full-boiling) pot of water; the water being about an inch in depth . Begin stirring the mixture while it heats in the roiling water bath. The mixture will soon become thickened as the Gilsonite melts, but keep stirring until it again becomes free. Done. If the jar moves while stirring, hold it steady with tongs. The entire process takes 4-5 minutes. Place a drop of the hot asphaltum upon a sheet of glass. It should cool to a soft blob which can be easily pushed and pressed with the knife, so as to allow free mixing with varnish or other additive on the palette. If too firm, mix-in a tsp. or more of turps while still hot, and again test consistency. Repeat until satisfactory. Put a lid on the jar.]

As shown, this Fir Wax works wonderfully for the purpose. You simply mix it half-and-half with your solvent-based asphaltum whereupon it will then work perfectly beneath the brush, keep its place, and be firm enough to paint over within half-an-hour or less. Based on my several years trials, no harm will ever come to it. Apparently, without much oil being involved, the solvent-'melted' Gilsonite pretty much remains as it became over time-- hard. This makes total sense, really. I hold some measure of belief that this is the manner in which Rubens used this usually troublesome paint; and with such lasting success ...though, as always, I cannot declare it..

One final mention here: Be aware that even with only the solvent as its liquifier, your conjured asphaltum will, in a month or so, become too plastic and gummy for best use. It will "liver", meaning it will become rubber-like and clotting within its container. The turps-thinned asphaltum is showing signs of somehow becoming polymeric. The heating with the solvent has awakened something long dormant within the glassy brown material; and this then alters the working properties. The malady can be somewhat countered by mixing-in a bit more turps, which will keep it for a few more months, though it will not be as well-behaved as when freshly-made. Perhaps the best thing to do is make-up your fresh asphaltum in small amounts when required; or just keep it in the fridge.

Update April, 2011: Within the past decade, members of MOLART have been involved with the study of asphaltum, Cassel/Kassel earth (AKA Cologne earth), Vandyke brown, and mummy. One of their goals was to find and establish "benchmarks" for identifying these various historical browns -- organic colors which so easily escape the limited capabilities of our modern day instruments. Overall, what the researchers found was the earths and Vandyke browns (essentially low-grade coals) contain much organic humus (rotting vegetative matter) which lead to eventual fading, wrinkling and shrinking/fissuring. Natural asphaltum in a solvent solution or drying oil was found to be inherently the least problematic and most successful of all these bituminous browns. Of course, this finding goes against the wisdom of so many, past and present, who claimed asphaltum the cause of such disaster during the 18th and 19th centuries. Instead, so many disruptive brown oil paints thought to be asphaltum were otherwise found to be varieties of Cologne/Cassel, or Vandyke browns-- or natural asphaltums composed of raw oils and agents that caused it to never solidify. [Some artificial asphaltums, such as that derrived from coal tar, were also found to be problematic/never-drying.]

During the lengthy study, samples of asphaltum oil paints were made using a modern-day artificial asphaltum (Shell Oil Company VEGA, a close match to a benchmark naturally-occurring Middle Eastern asphaltum) using historical 18th and 19th century recipes found in Merimee (asphaltum melted into various meguilp jellies and waxes) and Williams ( "Antwerp browns" made by burning the asphaltum to a cinder then grinding the residue in oil). The resulting sample asphaltum paints were subjected to aging and other tests to judge durability and stability. The findings were interesting. To wit, slow-drying issues encountered with asphaltum oil paint passages arise from its being prepared using regular untreated painting oils. Without the use of additional driers, such raw oils succumb to asphaltum's anti-oxidative properties and become very slow-drying. Other deleterious effects arose from adding waxes (Merimee), or even combining asphaltum with vermilion to create lovely flesh-tones. [The Williams cinder-approach worked well but harmed the wondrous color of the asphaltum.].

In other words, when prepared with a fast-drying oil (i.e., oil prepared with a siccative), the asphaltum paint did solidify properly and seemed perfectly safe, causing no actual harm to the painted work. Thus asphaltum, in and of itself, is not the 'n'er do well' culprit deemed such by so many. Instead, it would appear the various agents heretofore utilized to conjure the asphaltum paint and to make the paint BEHAVE itself have played quite a hand in that paint's eventual stability. It is unfortunate the researchers uncovered no other historical methods to allow asphaltum spirit and oil-based paint to ‘keep its place' upon the palette. I have personally spent many years using the S-P-F congealed varnishes (what I term "waxes") based upon Spruce, PIne, and Fir-- and Venetian Turpentine. All Gilsonite-based asphaltums seem quite stable via that route. Of course, the finding of pinene in so many samples of Rubens' paints allows me to somewhat speculate the master may have also been aware of these various coniferous-based "waxes"--every one of which would very likely provide the same finding. [Additional Note: In the early 1600's, Mayerne provided a formula for creating asphaltum. The recipe called for simply melting the crushed asphaltum into a strong drying oil. Based upon this MOLART study ...and recalling Mayerne's recipe, I hereby recount and somewhat alter my previous warning to keep oil out of asphaltum. Still, when using asphaltum for the underpainting --as Rubens appears to have done-- you should only make it as a spirit varnish; otherwise the useful inherent ability of asphaltum to quickly and firmly "set" (allowing gentle over-painting) will become compromised.]

The lengthy 2010 MOLART release can be accessed here:

Now to painting....

The following is my own rendition of painting in a Rubens' manner. I shall illustrate the method within a landscape instead of a figure-piece. Do not complain, for Rubens created many landscape paintings. Landscape painters also desire Rubens' technique; in fact, the second generation Hudson River School landscapists sought his method with a fever -- though they often resorted to having some wax in their mediums to attain it.

Important. Do not attempt this method using a modern day acrylic gesso containing chalk; at least not without sealing that acrylic gesso first. The chalk ingredient will present a rough and absorbent surface which destroys your costly brushes and generally thwarts transparent/translucent paint-facilty and brushstroke-retention. Also, stay away from chalk-bearing oil-based primers, as these, too, can somewhat harm bristle and suck oil from your paint. It is a mistaken modern-day notion that a gritty mechanical agent is required in an oil ground that will be covered by oil paint. No, not true. Of course, as king of your realm, you are free to oil paint directly onto an absorbent ground; but this was not Rubens' way.

Rubens used a chalk gesso ground on wooden panel. As I understand it, he even used this on a heavy woven canvas, too, as did many other old masters. The gesso was sealed by a coat of hide glue before any oily agent became involved. This glue coating kept the oil from ever finding its way down into the gesso. Above the glue Rubens applied an oil-based coating, usually an imprimitur; though it can also be a simple thin coating of drying oil; or drying oil mixed with some varnish. This dried oily coating atop the glue helps the solvent technique perform properly; and without it, the glue coating, alone, causes too much solvent-attack upon tender applied colorings. The result is a sort of 'melting' effect-- which some painters may like and take advantage of but, again, a visual inspection of the master's thinned paint indicates this was not R's way.

Following the Rubens approach, I first prepare a panel with chalk-hide glue gesso; or, in this quickly-put-together case, I grab a piece of heavy white paperboard. I can draw my design easily upon the tooth of the smooth raw gesso, (or upon this white paperboard); then, very important, I must completely seal the gesso (or white paperboard) with a single coat of pure hide glue. Again, I do not desire any oil or varnish being absorbed down into my gesso (or paperboard). The hide glue is perfectly sealing. It also dries very quickly and actual oil painting may begin soon after.

Now--very important to the function of the solvent technique-- before beginning to apply my composition and coloring, I wish to first demonstrate the application of a thin translucent varnish-and-oil-based imprimitur atop the glue coating. This imprimitur is an old device dating back to the Van Eycks. An imprimitur is translucent, allowing the white gesso ground to still have a sway with the colorings applied during actual painting. An imprimtur diminishes the overall optical brightness of the white ground while allowing the drawing, which was accomplished on the naked gesso underneath, to remain visible. The dried imprimitur also presents a pleasing and receptive surface upon which to begin your rub-in or coloring. Oil painting atop the bare glue sealer is, by comparison, quite unpleasant.

An imprimitur aids the transparent/translucent painting methodology by allowing several positive actions. The various transparent or translucent colors laid in atop a toned-down ground (imprimiture) gain a certain solidity and uniformity by decreasing the stainy flimsiness which can often and otherwise become unpleasantly-apparent; and this being due to the stark white ground showing through the thinly-applied coloring. Pigment graininess, dust, or other glaring faults seem to recede or entirely disappear by this simple light-reducing remedy. Darks can also be thinly-applied without need of loading on the paint. Without such loading, transparent shading more easily gains power and increased depth from the tone-down, too; ditto the brightening power of lead white touched-in later on when it is called into play to provide highlights atop the midtones. A colored imprimitur can also add to the general over-all atmosphere, swaying applied paint-colors towards warm or cool. [ For instance, in a landscape, using an orange imprimtur will tone applied translucent or transparent colors towards a sunrise or sunset time of day. A grey imprimitur tones translucent/transparent colors towards mid-day illumination. By use of this route, the very same basic colors applied translucent or transparently will shift in color-temperature.] As a final added bonus, the thin dried oil/resin-based imprimitur provides a wonderful surface that is so pleasant to paint upon..

I desire my imprimitur to dry quickly so that I can be at work on the morrow. For this particular grey-ish imprimitur, I take lead white and make it into a lean thick oil paint by use of some siccative drying oil or some sun-thickened walnut oil. I add just the merest speck of lamp black and re-mix to a mid-tone grey. Next, I add about 50% (half-amount) of the congealed Fir Wax. and re-mix the paint and congealed varnish together. I use the tip of my knife to scrap the "wax" from the surface in the jar. When I then mix this Fir Wax with my paint it creates a granulated grey. You generally have to look closely to see it. You will get this slight grainy effect with every color and the paint will dry with that effect, too, if you wish it. Adding turps and thinning the paint does away with it, to a large or complete extent.

OK, my grey imprimitur paint has been well-mixed with the "wax" varnish. It is now congealed. I'll need to thin it down for quick and easy application. To do this I add turps, or whatever solvent I desire, by dribbling it off the dipped-knife, mixing it thoroughly into the stiffened grey paint, producing a soft but still standing and exeedingly ductile fluffy mass. This sort of paint is full of solvent yet it retains a ductile resilience beneath the brush-- all due to the congealing Fir Wax varnish-addition.

Taking a big brush, I apply this translucent paint quickly atop my glue-sealed heavy paperboard, thus:

I go over the whole paper-board and even-out the imprimiture. Note how the brush marks become visible in micro-line hatchings due to the white ground shining through. I do not know what implement was used by Rubens to apply his imprimatur. He may have actually chosen a natural sea sponge, which will quickly and effectively cover the work surface, producing the very same striations as the brush. Now, you may rid the work of these lines if you wish by continuing to go over them with the brush as the paint sets. Rubens generally left the streaky lines visible. Maroger claimed these visible striations added a certain optical energy to the painted effect. Myself, I don't know why Rubens did it. Perhaps the striations gave visual indication as to whether or not the over-paint was sufficiently obscouring; and if the striations were still visible, then another wash of obscuring color was called for... Who really knows?

I allow this imprimiture to dry a day; or a few hours in sunlight will also suffice.

I now take some solvent-based asphaltum and mix that with an equal amount of the Fir Wax:

Now that my asphaltum is ready, I dip my drawing brush into solvent, then swirl my saturated brush into my asphaltum paint-pile to make a suitable drawing and sketching wash. Important! There is no oiling-out or need to lubricate the ground at any time within this technique. This means my paint will stay lean of the inherently-yellowing oil; and so it will remain bright.

I begin drawing in my design. Due to the congealed effect of the asphaltum plus some judicious solvent, I can draw effortlessly upon the dry imprimitur while capturing the hair-marks of the wet drawing brush. It appears as if I am painting in oil but this is solvent. I'm using Taklon synthetic brushes for this solvent approach. Sable or Taklon brushes work well, the fine hairs holding the solvent as it is carried from the bottle into the paint piles; then carrying the charged paint onto the work.

Note: As mentioned, many Dutch painters drew their design atop the raw gesso with a chalk or some sort of carbon -- sometimes even inking it over -- before sealing it with hide glue. For this demo I have no need for this preliminary drawing step, as I am simply making a design on the fly, inventing as I go. And so I sketch in a rough drawing atop my dried imprimiture.

Continuing with the quick brush-in.

Notice in the following extreme closeup image that the striations of the underlying grey imprimiture show clearly through the transparent brown asphaltum paint. This is quite typical of Rubens' sketches; and some of his larger works, too.

The next image shows the few colors I'll be using within this sketch. All receive approximately 50% to equal amounts (100%) of the Fir wax (iron oxide red at far right, which is a powerful tint and requires about 150%). Note how the mass tone of that iron red approaches the brightness of medium cad red. This wax-like varnish suspends pigments and engenders a noticeable simmering glow upon the colors. Anyway, exact amounts of the jelly are not so critical. You need enough to extend the paint into a transparent/translucent condition. The exceedingly powerful lampblack requires about 200%, while lead white may need about 25%+, depending on how 'solvent-tough' or translucent you require it to be. These decisions come through experience; it's not so critical, though. The Fir Wax will suspend and extend-out the pigment particles but there will be no eventual lowering in tone, as would happen when using oil-filled bulking agents (aluminum stearate, wax, chalk, or a fumed-silica gel).

If I were using a drying oil or megilp to apply my asphaltum, it would take days to dry. But not with this congealed fir varnish. There is no need to wait long for the asphaltum to set-up frmly. With set-up, I can now begin to "watercolor" my sketch with transparent/translucent paint mixed and applied by dipping my various brushes into solvent, just as I did with the asphaltum.

Here I am mixing up some blue for washing-in the sky.

Be aware that this solvent-application of paint is tricky. The application of the imprimitur above the glue-sealed gesso is quite helpful in the scheme, allowing the 'older' paint-layers to better resist the subsequent solvent-attack which occurs with each new layer (if you prefer to retain the pure white arising from the glue-sealed gesso, instead of a colored imprimitur, you should apply a coating of quickly-drying oil-- which is raw oil mixed with turps, a few drops of a drier, and some varnish to better harden it).The general rule is to apply the newest layer quickly then leave it alone until set ; or, if you wish utmost safety against solvent-damage, allow the last coloring to fully 'dry'. But as regards the first approach, after "set" returns, you can refine and blend, and carefully manipulate what has been laid down. But be careful, for to blend tender layers of "set" paint, you neeed to take Rubens' advice to Mayerne, which is to lightly dip the tip of your brush in solvent then facily stroke over the parts to be blended. Do it gently, quickly and no more than twice; otherwise you will likely pull-off the thin paint-- which can be a good thing if correction is required. And I caution here, especially if one is using mineral spirits, not to try and blend by force as the tender paint will crumble into tiny bits and specks. Use turps or spike, instead. Be deft and watch it as you go. If you see crumbling, use the solvent-moistened brush to stroke the layer back together.There is a sort of "plated look" created by this quick application of washes or glazes. You have to plan a bit. It will take much practice getting used to it. There is only so much I can relay by use of these images and basic descript. [Note: Rubens was not much into blending. He seems to have placed his paint on and left it mostly alone. If blending is your forte, await the drying of the Fir Wax paint then switch to an oilier or all-oil technique for your final layer/s. As a general rule, the more oil in the paint, the easier the blending; while the more Fir Wax in the paint, the less the ease in blending and the more the paint will resemble tempera.]

For example, the sky is a broad and rather uniform area. It will demand a well-loaded brush. Mix your requisite sky color blue, thin it down to a silky-cream and you're ready. Select a proper soft and wide brush for the job at hand. Apply the wash quickly and broadly and never mind going 'outside the lines' or painting over the asphaltum sketch. You will still be able to see it. Leave the blue off here and there for clouds, as the grey imprimitur makes a perfect base for later cloud-development.

Important! Though my asphaltum is firm against gentle and quick overlay of paint, it must always be borne in mind not to scrub too much or the underlying paint will come off. I mean, we are using solvents in a manner similar to water-color or egg tempera painting. But the great thing is, if I do decide to intermix layers or if I desire to pull a color off the work, it is easily possible to do so. Thus, I maintain and reserve a valuable trait I refer to as "correct-ability".

Note in the following broader image how the blue washes over the asphaltum without destroying it. Don't over-do it, though!

Now to quickly wash in some color in the hills and ground:

Next can come the local color of the tree trunks and foliage-shadows. Remember, all shadow colors especially will be transparent or translucent.

Now, atop the set-up shadow colors I can easly jot or stroke in some thicker and more opaque highlights. Opaque paint merely requires less solvent in the mix. The highest opaque shall reguire even less ....or even none.

Highlights and shadows begun upon the ground areas ...it's like simple watercoloring, though without any spreading or saturation....and you can do some blending later, where desired. As always, opaques shall come after setup of the applied transparent colorings.

Opaque details inserted on clouds and ground, wherever deemed fit. These thick opaques provide a visual balance and sense of solidity to the overall mostly transparent/translucent painting.

I complete the work in a little over an hour. I then allow it two days to dry well and become tack-free. Sunlight can speed thorough solidification of the paint. The painting dries with a perfect and pleasing uniform gloss and without need of a final varnish for many years down the road.

By-the-way, just how do I know a solvent-methodology was the very technique of Rubens? Very simple: He said so. Rather plainly, too. Read DeMayerne concerning Rubens and carefully perform your own translations of the French and Italian passages.* You will find Rubens mentions mixing his paint with varnish and also turpentine spirit. [*Yes, do your own translating. The current translations of the Mayerne manuscript have been performed by non-painters. This can lead to spurious information. In his 1848 book, Eastlake depended upon Merrifield to do the translations of Mayerne. I do consider Eastlake's versions to be the most accurate translations of any historically-available because the man was a fine oil painter, himself . Unfortunately, Eastlake was not a color-maker nor a varnish maker and much of Mayerne's words speak closer perhaps to those of us with the more rounded materials background. One case in point regarding Rubens, a part of Merrifield's translation is quite puzzling, especially if the person reading Eastlake grinds his own colors from scratch. This supplied translation reads: "Sir Peter Paul Rubens said that all colors should be ready-ground, employing for this purpose spirit of turpentine, which is better than spike oil and not so strong" (Eastlake, page 529). Now, this odd translation may well lead the reader to believe Rubens is directing that the colors are to be ground into pigments using a solvent; or that the pigments are made ready for mixing with oil by being wet with spirit. This translated advice never quite made practical sense, and especially so when one actually makes the attempt and tries to grind pigments using turps solvent instead of water-- water being the traditional perfect and safest agent for such. In practice it can be done but the solvent fumes will overpower the laborer! A better translation is not difficult to perform and seems the more fitting: "... the "colors" (meaning the actual oil paints) should be briefly worked up with turpentine spirit (Rubens actually calls for "essential oil of Venetian turpentine") in preparation for the painting session. Thus, Rubens is merely readying his oil paints with a solvent for easy brush application; he is not grinding colored pigments in it. As for the other possibility, wetting pigments with turps before rubbing them up with oil, well, that will only result in cracking under-bound paint. Oil paint is best made using dry pigments....and oil. Add the other agents to it afterwards. See Eastlake for the original Mayerne text including Merrifield's translations; then get to work.]

Again, I cannot say with certainty whether this congealed fir varnish was the master's very own means. Still, it does match the jelly-like brushwork and performs fittingly. Plus, something I consider highly indicative, this congealed varnish does wonders when used in conjunction with the nefarious asphaltum. As for resulting resin-markers, I can also suspect pinene will show up in the paint at some future date. In the end, though, it is all merely a best guess scenario on one man's part.

One more thing: Do not allow the Fir Wax treated paints to dry upon your palette. Regardless the solvent abundance, your paint will dry with a toughness similar to copal or amber-based paint.

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Final

Though this quick little sketch was made throughout using much solvent and in a tempera-like or watercolor-like methodology, it still appears in all stages as an oil painting. It does not look like a watercolor or a tempera painting. This appearance is due to the superadded stability of the congealed fir varnish. The paint is not a stain; it has definite substance. A painting of this tempera-like manner cannot be made using simple-oil-and-pigment paint coupled with a solvent. Why? Well, as instances of thoughtful merit: Using asphaltum would be out of the question. The amount of solvent required to pull this off would engender running, trickling, or spreading after placement. The thinned-down paint would not retain brush-hatching. Layers would not truly "set" with solvent flash, which would then dis-allow further added over-washes. In addition, the paint would not be bound properly. The work would never dry to a shine, let alone a gloss; and instead it would be dull and powdery-looking. There would be no resistance to atmospheric-attack; the painting could never be washed with water or anything else. Varnishing the work would help somewhat but even that procedure would be done at great risk to the tender paint.  

Warning! This Congealed Fir Varnish and the above example technique should not be considered by anyone sensitive to solvent-use. Still, for those who desire to paint in the Gentileschi, or an all-oil manner, Fir Wax can be made into a megilp-like jelly by mixing-in 25-30% drying oil or sun-thickened oil to some of this jelly on a sheet of glass. Thereafter a megilp-like performance and painting technique can be used. I recommend the type of oil to be walnut, as linseed oil will generate more yellowing and wrinkling when used with handmade oil paints-- or most any oil paint.

Fir Jelly might be customized to even greater toughness by the addition of any of our amber or copal varnishes without losing its congealed character; still, the amazing toughness of the polymerized fir resin alone, by itself, seems to match the actual and final strength of copal. Thus, I believe use of such additional agents are unnecessary. Note: Though it has a good shelf-life, Fir Wax should never be heated and might best be stored between use in a refrigerator.

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Additional Background Notes and Rants

Notes and Rants (I) Medium-Rich paint: Rubens painted with much medium. His work shows-off what I would term an overall "medium-rich" look. Some might think I mean Rubens painted with much oil. No. In fact and as I mentioned earlier, Rubens was chastised by his contemporaries for painting with too much varnish. These critics decried the underlying transparent/translucent paint and admonished the master that his work would not outlast his own mortality. Let me share with you, transparence and translucence are the greatest keys to the finest OM masterworks. Prior to the discovery of the Van Eycks, the Italian Cennini promoted the technique of oil painting only in an opaque fashion. What soon-after revolutionized oil painting was the novel technique introduced by the Van Eycks, which was primarily a transparent/translucent method of using oil-based paint. If you will but read Karl Van Mander's own words (1602) then you will understand that the majority intent of the 14-1500 Northern painters was to paint primarily in a single-layer, and in mostly see-through fashion, adding solid highlights only and strictly where finally needed. Some experts today say this is not so, and that the 19th Century oil painters were delusional in their search for transparentizing mediums. Take caution when you hear such defamation, for the very greatest optical effects allowable through oil paint arrives primarily through the use of transparence and translucence with super-added opaques in the highlighted areas only. That wonderful and amazing optical-richness and depth can come in no other way! Midtones and shadows must be primarily transparent and translucent; and by vibrant contrast, the shining glowing brights can come by piled-on opaques, but not at the expense of the subtle and also-glowing midtones and shadows, whose marvelous and complimentary richness yet descends from the underlying priming.

This was all established way back in the 1400's. Again, do not accept the words of anyone today who tells you the old master's paint was not primarily transparent or translucent by original intent and design; and that it has become so only through the benevolent hand of Father Time. [Note:Yes, indeed, some sorts of oil paint may certainly become translucent with time. For instance, simple oil-and-pigment lead white without the ample addition of a strong resinous varnish to lock it from atmospheric-attack will (will) become translucent with time, just as if you had gently cooked the two ingredients together ; only the combination will occur interminably slower. Over time and helped along by oxdation, the oil actually dissolves the lead carbonate and the two become united in either transparent or translucent lead-oliate. Look up "pentimenti" to see what it is, though no source will tell you what causes the effect. Now, this combination of lead carbonate with the oil is a failing not noticeable in Rubens work; or Jan Van Eyck's work well before him. All opaque touches of lead white remain pretty much as these particular masters intended. No, I'm not making this up. If anyone wishes to acquaint themselves with historical visual descripts of either Van Eyck or Memling or Rubens or Durer or Bosch, Belini, Leonardo, or most any other worker's paintings as they appeared to the multitudes down through the centuries, they will always find the same mention of the lucid supporting transparence visible here-and-there throughout the work, and coupled with opaque highlights where necessary. You will find no historical account maintaining these painters worked overall and mostly with solid opaque paint. Instead, that was Cennini's primitive, limiting, and so-inferior method. Cennini came before the Van Eycks. He tells us to mix tints to the color we visually discern; then we shall apply these mixed tints opaquely. Yes, some amazing painting can come via that route; and after all, that was the predominant method of the impressionists ....which fellowship held such sway at the end of the 19th C., as to allow we of the 20th to descend to a limited and backwards-state in craft. The primarily transparent/translucent methodology introduced by the Van Eycks has been buried and lost to us. It is unfortunate that this opaque manner of oil painting has been adopted amongst the majority of oil painters in our own time. Again, the method is not without some amazing charm in many instances; however, due to the overall limitations encountered when applying the opaque manner towards a tight careful realism, it is no wonder that, today, egg tempera has re-established itself among many as the better means to reproducing such.]  

Notes and Rants (II) Oils and Oily Paint: This 'jelly' varnish is quite different from megilp. Megilp is an oily medium. Fir Wax is a lean varnish, being mostly fir resin. Too much megilp in your paint will cause all the faults of the oil to become manifest. By contradistinction, too much of this fir varnish in your paint causes no negative effects, whatsoever. In fact, to garner the best manipulative effects from megilp, it is necessary to mix substantial amounts of the jelly with the paint. That will eventually lead to a faulty painting, yellowing, wrinkling, etc. But adding 100%+ of the Fir Wax to your paint allows every bit and more regarding wonderful manipulation, and without adding any over-abundance of the oil. Yes, this is what I have found through many trails. My paint remains bright.

Be aware of something that is seemingly unknown or disregarded today among oil painters: Oil is both lord and devil to oil paint. Oil is at once the most evil but also the most necessary and creating-ingredient. You will read everywhere that resins are the blame for yellowing, browning, powdering, wrinkling, weakness, and on and on. Nope, the primary culprit causing yellowing/browning, wrinkling, etc., is the oil, itself. The various resins associated with historical oil painting have remained clear and bright in damp-darkness for thousands or millions of years. No painting oil can ever come close to that feat, as it would quickly oxidize, dissolve, or carbonize underground, or even above ground, as often occurs in humid climates. As for oily varnishes or mediums, those concoctions yellow in proportion to their oil-content; not their resin-content.

I repeat, oil is a relatively weak and faulty ingredient in oil paint. Were I able to get rid of that particular troublesome agent, my paintings would remain clear and bright and never sallow ... well, excepting from atmospheric attack/rot --effects which can be mostly alleviated by the simple act of a final removable resin varnish layer atop my so-carefully-built work. Let that final layer suffer the atmospheric-attack; then replace it when it does. Everything lying beneath that final varnish will remain pristine. This is the best route to bright oil paint. Truth is, I have found that those resins historically-known and utilized within oil painting practice are quite durable and non-yellowing, either in damp, darkness, or lightness; and fir, copal and amber ...sometimes larch and certain light pine and spruce ... are considered the very best. No, it is the oil constituent that yellows the most and by far. Wrinkling? Yes, that is due to the oil, too.

There are of course variables involved with this simple overview, but the gist of what I'm telling you is accurate. The most yellowing ingredient within oil paint is the oil; and so we should keep the oil-content as low as possible. [In case you might disagree, go right ahead and coat your next cured painting with a final layer of linseed oil. Oils yellow inherently and this just necessarily begins at the point where curing is reached. Untreated drying oils typically reach their cured stage rather sooner than treated oils; thus the untreated oil is seen to yellow sooner. Adding a siccative will, of course, speed curing; hence the yellowing. The treated oils become semi or mostly polymerized; thus they can take months or years to lose their "tack" and become cured. But then they yellow, too. Science tells us the degree of yellowing is directly proportional to the oil's linolenic acid-content. By contrast, durable resins yellow predominantly when compromised by atmospheric-attack (mostly by moisture). If kept from a harsh environment, decent resin varnishes will show only modest yellowing in a hundred years. Ask the Tate Gallery about their Holman Hunt painting which is still thinly-coated with good copal since the day he performed it. They report it is noticeably degraded but not to the point of requiring removal. And for those who think damar spirit varnish soon yellows, next time make it yourself using good turpentine-- and don't add any linseed oil to it (the linseed oil will yellow, of course-- but the damar will receive the blame). As such your good damar varnish will last thirty years on the wall with only a minimal yellowing. BTW, dried oils get attacked by the atmosphere, too. That attack gradually reduces an oil to carbon; and this process happens much faster than with a durable moisture-resistant resin. Again, vegetable drying oils, alone, offer little resistance against moisture-attack; but as for those same oils combined with certain resins... well, that is an entirely different and much-tougher critter.

Back to oil and yellowing: The future yellowing or sallowing of a painted color is neccessarily dependent upon how much of the oil-ingredient is visible. For example, say ultramarine blue plus some white is apllied to your sky. If the pigment particles sink down and the oil rises, the work will soon show yellowing. If the blue dries and the oil sinks away, the pigment particles will pretty much hide the oil, leaving a sky blue color that remains rather bright. This is due to the hiding power of the pigment. The more pigment and less oil, the less the oil is seen to yellow. Yes, the oil within the sky-blue shall yellow soon enough; yet, for the most part, the over-abundant blue and white pigments will obscure or hide that yellowing.

Now, anything that increases the oil in that sky-blue paint will increase the eventual visual-yellowing, too. As example, when the oil-content is increased within a paint, the pigs will be scattered further apart from each other, with the inherently-yellowing oil filling-in the space between and surrounding. Thus, adding additional oil or adding oily bulking-agents to your sky-blue paint will decrease the hiding-power of the pigment. This is the latent problem when using cheaper or student-grade paint. Such paints have been bulked-up with aluminum stearate, wax, bentonite, pyrolized-silica-- I've even heard of using mica flakes. Chalk is another bulking critter. Like silica, chalk offers nothing in the form of hiding power against the oil's future darkening 'sneak-attack'. All of these bulking agents increase oil-content and rob pigment-load; thus to decrease the hiding ability of your fine pigments. Of course, adding slight amounts of silica, wax, bentonite, or chalk to a pigment will have little effect on amounts of oils in the whole; however, there is a current trend to actually construct paint-extending oil gels and paste out of these materials by mixing them with oil. This practice amounts to making transparent or translucent oil paint! That's a no-no simply because there is nothing within such gels or putty to hide the eventual darkening/browning of the oil-binder. If you desire to paint in a translucent/transparent manner, simply apply your colors thinly -- there is no need to bulk your colors further using a substance heavy in oil. Adding these oil-y gels and putties to your oil paints will necessarily darken your colors. The results may not become manifest for months ...and the deepest darkening --which is a rotting of the oil film due to atmospheric-attack -- will take years; but 'down the road' your painting will become increasingly subdued-- perhaps even to the point of darkness. This malady is well-known and lamented over if you read through the various centuries. Every writer wonders why their own generation's oily-works are turning dark and dingy. They point to various earlier schools of oil painting, such as the Venetian School, whose master-works have somehow remained bright without darkening. They then hold up these schools as benefit of certain viable painting secrets. The means of their glowing works capture the minds; and yet we painters continue to use over-oily mediums, the worst offenders using linseed combined with bulking-agents. I repeat here, too much oil and not enough pigment to hide its inherent faults results in too-noticeable yellowing/sallowing/darkening. {*Note: a few restorers and conservators are finding amounts of chalk in certain Old Master paintings. True, chalk and other fillers show up in some of the old works. I'm rather certain this finding is simply due to an age-old scheme, a practice that has historical mention: Pigment-makers have used ground chalk and white kaolin, barytes, etc., to extend their product and improve their profits. Then again, pigments with added chalk and mean't for house-painting were also readily available to the buying painter, who might themselves prefer to save a coin. I'll also mention the historically-known use of colored chalks to outline figures betwixt layer's, too. And so you see there are several manners or mechanics for finding chalk within an old oil paint or paint-layer. Whichever, whatever the reason, adding-in chalk will not improve the color of any resulting oil paint. Ground chalk in all sizes is quite absorbent and it increase the amount of grinding oil needed to work-up a color. Soest and Gandy, two of Vandyck's students, do mention a chalk-adulterated lead white called "loos" white as being available, but they also say their master was careful not to use it.}

{Also note: I might see a bright spot of light if modern bulking mediums, such as chalk, fumed silica, or wax, actually lent moisture-resistance or aided the relatively weak binding-power of the oil. They do not. I recognize modern synthetic alkyd resins are being incorporated in some versions of these bulking agents. That addition represents an improvement in strength; but still, less pigment and more oil-bulking means more eventual yellowing/browning. Some enthusiasts say they have found ways to keep their oils from yellowing; though I do wonder if they have actually followed their trials with the many year's of final observations requisite to verification. Again, science tells us the yellowing is due to the relative linolenic acid-content inherent to the oil. Anyway, if some painters have managed to find a way around this then I must applaud them, and rightfully so. Pacheco, the teacher of Velazquez, supplied a rather-involved method for 'purifying' his linseed oil; yet when he bragged about being able to paint blue skies using his linseed oil without fear of yellowing, his secret turned out to be that of simply adding spike lavender to his oil paint. In practice, the evaporating spike allowed Pacheco's 'purified' linseed oil to sink down from the surface, leaving the blue sky color dull and lean of oil...and rich in pigment! Yes, that will work, though a certain deadness follows dull paint; and so you apply a top-coat of clear durable varnish. History gives many other recipes for supposedly cleaning oils; I have no doubts the followers of such methods, having spent great time at their task, if nothing else, felt better about their work.[Note: In 1632, Vandyck extolled the use of linseed oil above all other oils, and by way of preparing it via a certain odd 'purification' method. By the time of his death some eight years later, he had switched to walnut oil.]

But to stop the yellowing of linseed oil ...? Myself, I have failed at that through any and all attempts at 'clensing' my oils. Some early attempts showed exciting promise, only to fail within the following months or years, when the oil or paint-film finally cured (fresher and untreated oils generally cure much faster than aged, bulk-oxidated, or heat-polymerized oils-- the usual exception being 'blown' and "sun-ed" oils). Thus, I do not possess any reasons to presume oils can be made non-yellowing by subjecting such oils to what is called 'cleaning'. I won't worry about it, though. I'll keep my paint on the lean-of-oil side and dose it only with historically-dependable resins instead of oil. It will be much better bound and resistant to atmospheric-attack. I can even apply it very lean by the simple use of a solvent. As a pre-requisite, like most of the early oil painters, I'll also prefer nut oil over linseed; and I shall not attempt to 'cleanse' my nut oil beyond allowing the foots to settle out. Again, I have found nothing offering further gain. If you would not accept my own word in this matter, then bear in mind Titian said this*: " If you have good oil, you can make a good picture ; if you have bad oil, you can still make a good picture." [Apparently, and if this attributed quote has historical merit, this great painter, who was known for creating the very brightest works, did not depend on the cleaning of his oil. This attributation might also indicate Titian used a solvent in his own technique, which would incur the sinking of the oil away from the paint surface, rendering any inherent penchant to discolor much less of an issue.] *See Merrifield; "Original Treatises...", page CXXII

Below is an image comparing a commercial artist's best refined linseed oil, foots-separated unrefined walnut oil, and foots-separated flaxseed oil. If you have read through my website you will likely recall this image. If not, allow me to introduce you : On a strip of window glass, all three oil paint samples were compounded exactly the same way with equal amounts of oils and lead carbonate, then applied to the glass in rounded piled blobs. The sample was then laid flat in a daylight-lit room. The nut oil in the center dried the fastest (4 days) and did not collapse into itself, wrinkle, nor turn yellow, as did both types of linseed oil. [To contrast the relative outcome and effects, dark blue mattboard was placed beneath the glass before photography.]

It can be seen that both linseed-based lead white show more yellowing and have collapsed inwards and wrinkled, while the walnut-based lead white remained upstanding, rounded and wrinkle-free. Walnut oil shares this inherent ability to resist oil paint-wrinkling with poppy and sunflower-seed oils.

The following before-then-after images show the effect of placing this same test-sample in a drawer for two months time; then subsequently exposing the darkened and yellowed paints to direct sunlight for three-days duration: All samples show the bleaching effect of exposure to UV. The non-wrinkled walnut oil sample regained brightness the quickest, its oil-y pellicle uniformly covering the paint blob. Not so with the linseed/flaxseed samples. Unfortunately, during initial drying, collapsing and wrinkling of the linseed/flaxseed-based whites interfered with the uniformity of the oil pellicle. The oil essentially gathered more within the wrinkle-valleys. This results in an even greater apparent yellowing, making a bad situation even worse-- and requiring many more days of UV-exposure for remedy.

In the realm of mechanical bulking agents within oil painting and the typical effects garnered through their use, I present this illustration:

The following image shows, far left, "water-washed" flaxseed oil. This oil was shaken numerous times with common tap-water. An orange sludge made up of oxidized and rotted oil-particles gradually precipitated from the mass and formed at the bottom. [Note: A.P.Laurie termed this gook "mucilagenous and albumenoid impurities". Uh...no, it's just what becomes of water-emulsified oil. This sludge is simply artificially-produced and rotting 'foots'. It results from the emulsified yellow-ish 'cloud-layer' betwixt purer oil above and the water below-- in other words this cloudy layer is nothing more than microscopic oil-particles which combined too-intimately with the turbulent water. These oil-particles soon succumb to the "O" part of the H2O: The atomized oil particles oxidize and cure. Afterwards, the resulting hardened particles then simply rot via the degradative-attack of the surrounding water ...and sinking away from the oil-water mix. If you doubt my words, syphon-off some of that yellow-ish cloud, place it upon a sheet of glass and allow the sun to bake-off the water. What you will obtain is a thin layer of flaxseed oil; and it will soon dry and behave exactly like a comparable layer of the 'pure' oil. What I mean is, the film will yellow in shade/darkness; and it will become clear again when subjected to sunlight.] As the "washed" flaxseed oil thickened and became more and more acidic (rancid), it polymerized to the point where its hygroscopic ability to emulsify with the shaken water became less and less. Re-iterating, this 'less-shed' effect is nothing more than the result of polymerizing oil becoming more resistant to water-permeability. Know that a fresh oil is more permeable to water than an aged oil. And so, after reaching this stage, my altered flaxseed oil was carefully separated out from the water and orange sludge, then shaken and stored with an addition of lead carbonate ... which eventually rendered it nicely clear and fast-drying. [Note: There are many ways to "wash" oils but this version, which I used in the 1980's, comes down from the 1600's. I do not often paint with artifically-aged semi-polymeric oil--such as this oil-- as these oils produce long paint and my own preference is towards the short. As I have said before, such oils firm quickly but remain un-curred and tacky for a very long time, which, with most pigments, greatly hides their eventual inherent yellowing nature. [See my web-page on Siccatif de Courtrai.] The second grey dab in the photo image is chalk paste made with the same treated flaxseed oil. Though my chalk is the very material I use to make brilliant white gesso, the addition of oil produces a nearly translucent (thus grey) paste. The third blob is Halstab triple-A lead carbonate mixed into a stiff lean paint using the same flaxseed oil. Far right is a glob of resulting paint when the chalk paste is added in an equal amount to that pure lead white paint. In the photo, this simple 50:50 combined chalk-paste-and-lead carbonate paint looks much less-white than the pure lead carbonate paint. I have read, some artists say the brightness of their colors increases when adding chalk paste. That may appear correct in the wet state; however, realize, pure chalk paste is grey; thus, adding this bulking agent to my colors will necessarily dull their color-brightness. With the addition of chalk paste, whites become darker while darks become lighter.

Now the same sample as it appears after sitting face-up four months in a dimly-lit but not dark second-floor room:

There is nothing quite like the old master's favorite white to sooner reveal an oil's nature and capabilities-- both in the treatment of the oil and the immixture with that oil to create paint. Lead generally causes raw oils to reach their cured and polymerized state quicker, thus to uncover the oil's true faults. Titanium and zinc prove to be much more hiding and forgiving. In the illustration above, final curing has overcome the washed flaxseed oil and reveals that washing to have had no remarkable effect against the oil's inherent yellowing. Moreover, adding chalk paste to my lead white has ultimately engendered the oil's latent yellowing to be more visible due to increased oil-content plus the overall ratio/reduction of lead pigment within the paint. [*Important note: I was very careful to lid my "washed" and lead-treated oil and to leave as little air-space as possible in the storing jar. You see, oils noticeably thickened by lead-treatments and/or oxidation can become so polymeric as to actually revert to a slow-cured state quite similar to today's commercially-produced standoil. No, I wished my treated oil to remain as thin and fast-curing as possible. Old "black oil" and lead paste also behave poorly as to cure-rates; ditto oils treated with too much siccative. I personally have samples of thickened lead-treated oil that have remained rubbery and un-cured since the mid-eighties--and still tacky at the touch. It should be borne in mind that any oil which cures slowly will not reveal its inherent yellowing nature until it finally does cure. Some may think this a good thing, i.e., allowing the oil paint to remain wonderfully flexible, but know that any oil that remains uncurred for a lengthy interval allows likely and unhappy reactions with certain pigments. For instance, lead carbonate will react with the acid in that uncurrred oil and become lead soap-- a substance that is transparent. In essence, what happens is the lead white paint becomes increasingly transparent over time. BTW, it is historically mentioned that this saponification can be remedied by the simple act of adding a powerful resin-varnish to the oil paint. I believe there is truth in this old assertion, as a proper varnish typically hardens --cures--oil films. Be aware, the Pre Raphaelite painters liked hard paint. To achieve such paint, these craftsmen were fond of adding resin varnish and zinc to their paints. As their work shows, sooner-hardened paints produce the better state for oil painting longevity. This hardened condition of paint idea goes against oil painting practices being promoted today; yet it is true that hard paint will be more durable than soft, that is, if proper attention to the rules of craftsmanship are adhered to. But, yes, agents that produce hard paint are criticized nowadays. This is unfortunate as too many young painters are willing to put faith in the newest claims, especially if the label of "science" has been conjoined with such. Always remember that the greatest science of today will be considered matter from the Dark Ages tomorrow, and that the gathering of scientific facts is different from the all-too-human interpretation of those facts. As perfect example, consider that zinc I've noted as a favorite of the PR painters: According to one such "scientific" claim gathering momentum today, zinc is bad for oil painting. Hmmm.... I won't be buying into this "science". I wish it known, zinc is a wonderful addition to oil paint; and yet it is currently condemned outright, even though history shows it as long-used and desired as a paint-hardening agent. Recipes for its use to speed the curing of oils, as a sulfate, or calcined into an oxide, date back to the 1400's. The famous recipe for "Oleum Preciosum" mentiones use of "copperas" -- which is zinc sulfate-- as a final addition. Many past researchers (such as Merimee, Eastlake, and A.P.Laurie) believed the zinc sulfate was added as a siccative. No, as I learned from actually making this oil, the actual drier in the recipe is calcined sheep bone. As for the copperas, that ingredient was added as a curing (hardening) agent! I know from experience that without the zinc, the wonderous "oleum" will remain tacky for a year or more. And so I will admonish you that zinc was and still is a valuable agent to our time-honored craft. A hundred-and-fifty-years ago, the PR painters preferred zinc oxide white over lead white as their primer, as well as an addition to their colors, where it has done such great service. Fellow oil painters, use zinc and do not fear it. Resin varnishes will harden oil paint ...and so will zinc. Zinc will also solve the too-flexible, oil-saponifying and yellowing nature of lead white. If no one else today will tell you, know this: Zinc oxide and lead carbonate should be combined for the very best white of all those whites available to us. History has shown this as fact. And while scientific thought changes considerably over time, the historical record does not.]

As I mentioned earlier, perhaps some good researcher "out there" has come up with a way to actually thwart the inherent yellowing of linseed and other oils*. That would certainly alleviate one aspect of using chalk paste or another bulking agent; though, still, what about the greying-down and subdued coloring effect created by adding chalk or other to the paints? Why would a painter prefer to paint with oilier colors and subdued chroma capability? Are these aspects to be sacrificed for increased translucency/transparency? [*Note: I am aware of one way to create a practically non-yellowing walnut and linseed oil-- not through washing but, instead, through a cooking process. I use this process to create our "Heat Polymerized Walnut Oil"; but I remain so far uncertain if actual curing has taken place within my samples. The earliest of my samples remain yet non-yellowing and have out-shone commercial standoil ...Still, mine eyes have been fooled before into making and stating false conclusions...]

There are various differences betwixt mechanical bulking agents and proper resin varnishes when these agents are added to oil paints. As one example of this difference, a proper varnish-addition to a paint will increase the visual intensity --chroma--of that paint color .... whereas a mechanical bulking agent will decrease that intensity. [Note: Fumed silica is a bulking agent which forms a transparent gel when added to oil; thus it somewhat matches the use of a resin varnish. For instance, silica gel will beautifully transparentize any paint color and make it appear more intense while wet. The downside? The additional oil-content delivered to that color will soon lead to increased yellowing of the paint. Also realize that fumed silica is a "flatting" agent-- this means the colors will lose their initially-generated visual intensity upon drying. By harsh comparison, proper use of a decent resin varnish will neither increase inherent yellowing of an oil paint, nor cause dulling in the final dried film.]

To sum-up this rant, in oil painting we still need the oil. Regrettably, we cannot achieve the wonderful effect of blending without having this oil-ingredient in our chosen paint. No, we simply cannot rid it from our craft. After all, this supreme ability to blend is the plus-factor available to our paint that is missing from those so-numerous other methods. Okay, that's why it's called oil painting. We need the oil but we need to limit its ratio to pigment as much as possible. The use of proper historical resins and solvents can greatly help in the construction of a colorful and durable oil painting.

Update Feb. 2011: The following images show another and more-carefully made example of this Fir Wax/solvent technique.

"The Cumberland Narrows, Lovers' Leap" 18"x24".

Above: The asphaltum sketch sets-up allowing an immediate wash-in of superimposed colors. Each applied color also sets to some degree, allowing further coloring and correction. At any stage, the whole can be washed back to the sealed ground. Incidently, do recall my advice of using an imprimitur atop the sealing glue-layer. This imprimitur, whether colored or clear, aids the superimposed application of the oil paints in every way. Instead of applying a grey or colored imprimitur atop the sealing glue layer, I chose to go with a clear coating in this instance, so as to retain the pure white of the chalk gesso. I used Fir Wax mixed half-and-half with oil, then slightly-thinned with turps. It worked well with the applied asphaltum and coloring layers. This clear imprimitur was dry in 24 hours, allowing me to begin with my sketch-in using the FW-treated Gilsonite asphaltum.

Above: Nearly finished-- highlight-colorings, such as leaves, etc., are performed opaquely. The painting drys to a glossy surface by itself, requiring no final varnish. Throughout the work, the seductive asphaltum under-sketch peeks through the overlying colored glazes and scumbles. There is an optical richness to this manner that cannot come through painting with opaque color-mixes -- which, again, is the near-universal oil painting approach being practiced today. The applied paint shown here is transparent/translucent, excepting where the brightest highlights occur. This primarily transparent/translucent painting system using Fir Wax is not for everyone; still, it can be quite the show-off at producing glowing full-sunlight and simmering half-light illumination.

For a constructive demo regarding use of Fir Wax and asphaltum to create and colorize an "optical grisaille", go to next page.

Copyrights to James C. Groves, Frostburg, Md. September, 2008; updated December, 2008.

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