Groves' Genuine 19th Century Siccatif de Courtrai $20.00 per 65 mil. plastic bottle with dropper cap.
A very powerful drier made with both lead and manganese. One small droplet of this drier
added cold to an average paint nut (i.e., a rounded pile of oil paint equal in approximate
diameter to an American 25-cent piece) causes speedy drying in as little as 8 to 12 hours-- a trait
that is especially helpful in the underpainting.
A siccatif (or 'siccative') is a 'drier'. The actual underlying mechanics as to why a siccative catalytically makes paint become solid sooner than it normally would is not truly known. Some say the sic delivers or attracts great amounts of oxygen and this causes the polymerization of drying/solidifying. Frankly, my eyes cannot see things on a molecular level ; and so I don't know how it works. Besides, other mysterious elements besides oxygen speed the solidification of oil paint. Sunlight certainly does; and so does heat. Interestingly, if an oil is bathed in direct sunlight for an hour or so, it will begin drying and proceed to such end rather quickly -- and, BTW, although a nice heating is helpful, once the sun activates the 'drying' effect, this happens even in cold weather. Molecular confusion aside, I still realize this: adding siccatif to oil paint greatly speeds up this normally tedious and slow process of oil's ultimate polymerization into a solid. Thus, a siccative surely has great value for those of us who live by paint.
Yes, speeding solidification of oils and paints can be of great service. For instance, the painter might be using a carbon-type black--something I am personally fond of. Of course, many other colors such as the cads are also slow driers ; and need I mention today's so-commonly found safflower-based titanium and zinc tube whites?
I offer several drying varnishes based on lead alone. By slight use they typically allow perfect drying overnight while not interfering with the daily workings. But our Courtrai siccatif is decidedly different. According to some older writings (for instance, see Vibert and Church's words given later in this report) Siccatif de Courtrai was saturated with much lead and manganese. I have to wonder about this characterization. Why? Because, the truth is, our own highly-effective Siccatif de Courtrai actually contains rather small amounts of those same metals ; and yet it packs an amazing punch to produce the 'drying' or solidification of regular painting oils.
Regardless the amounts involved, just how safe to oil painting are these metals lead and manganese? Lead is once again considered a safe drier for oil painting ; and it dries while lending flexibility to most paints. We should recall that, during the later half of the 19th C., lead was considered a 'bad' drier. It was said to be "progressive" in its effect and would assuredly cause the rabid embrittlement of otherwise-sound oil paintings. In the same time-frame, manganese was considered the best agent to creating drying substances. This sweeping judgement, based upon the then highly regarded scientific examination, actually led to lead being dropped from many painter's palettes for the next hundred years, plus. Zinc white, and later, titanium white, took the primary role.
Today, the roles have reversed. Manganese is now claimed to cause embrittlement of the paint film. Yet manganese is a valuable ingredient as a siccatif. Comparatively sampled, it is a much faster drier than lead. But what has been known for centuries is this: a combination of these metals cooked together with oil and other materials--the metals in a certain odd ratio-- allows the benefits of both to shine through with no apparent detriment to the oil paint..
Darkening is associated to both these metals (and copper, too). There is good reason for this association. Either lead or manganese (or copper) when cooked into oil will cause that oil to darken -- even blacken if heated enough. But here is the surprising thing: though the resulting cooked oil is certainly darkened by the metals, as long as it is not burned, there is no actual carbonization ; and the darkening is, instead, a fugitive coloration, i.e., not fast to light. The result being, the darkness 'goes away'-- and often this happens quickly and upon simple drying.
[But there is another noticeable bug-a-boo about manganese. I might generally say this fault is
intermittent. Still, it can happen so I will mention it. Yes, indeed, when cooked into an oil,
manganese makes a powerful drier. Though then in an oil solution, this metal can react with
certain other metal-based paints. In fact, one of the most reactive paints to manganese oil is lead
white! I have personally witnessed lead white soon become a dull sallow light grey when a small
amount of manganese-made drier was added to it. Though not noticeable at first, in 15 minutes
the white has turned gray! Upon thorough drying, this grayness, to a large extent, 'goes away'.
But it is still noticeable. Of course, only a very tiny amount of the manganese-treated oil should
ever be added to a paint --especially one so naturally fast drying as lead white. Also, no such
discoloring chemical reaction is seen when zinc or titanium whites are used in place of lead
white ; or if the lead white contains these other pigments. Again, just thought I would mention
this for it is seemingly unknown today.]
If you aren't already aware, the use of driers within oil painting is a sticky subject for some. Vibert and Church were early critics of siccatives. Vibert wrote about Siccatif de Courtrai in the later 1800's. He found it objectionable, even though many professional painters were apparently using it with perfect success ( and, based upon the fine present condition of their works, we can still allow this judgement ). Vibert was distressed by the commercially-prepared siccative's dark color and manufacture. Accordingly he stated: "The colourmen do not make the siccatif themselves, and the majority of them do not know how it is made. They ... insist that it should be very black...so that the manufacturer, who might with care make a better production, is quite at liberty to let all impurities pass, since it is never sufficiently dirty, and is obliged to add lampblack to it." Vibert also cautioned users to be careful in their additions of this siccatif to their paints. He noted the predominant carrier was turpentine and, as such, some many might use the sic to thin their colors instead of regular turpentine or other agent.
Another well-known authority on artist's materials during the later half of the 19th Century was Sir Aurthur Church (not to be confused with landscapist Frederick Church, who, BTW, was also a fond user of such fast-drying devices). Church wrote in his handbook that Siccatif de Courtrai "is a very dangerous mixture, heavily loaded with compounds of lead".
Note that Church implies nothing demeaning about the other main ingredient, manganese. No surprise there. It should be remembered that lead was being blamed for all sorts of painting maladies within this particular later 19th century time period. You see, lead, in the form of paint and other guises, was 'out' (thankfully, today, it's come back ; once again, lead is recognized as the safest and toughest drier for oil painting). As for 'safe' metallic driers, manganese was then considered the more blessed drying material -- though it, too, was later condemned when cobalt took sway ... and this not-with-standing the chemical graying reaction I alluded to above.
Since the 19th Century, many authorities have added their 'two cents' regarding driers in oil painting. Read up on the subject in Mayer or Doerner, or other. You will receive all sorts of confounding advice/information/mis-information when looking up driers in various sources.
My own opinion? Well, I don't know everything but I can tell you this: little I've read from within the recent past and present concerning the use of driers appears to be backed by actual oil painting experience in the matters. Mostly we'll find quotes given from previous authors and studies that arrive from anybody and everybody except actual oil painters. I have made Siccatif de Courtrai many times and utilized it often. All I can say is Vibert appears mistaken and so does Church ...and all the rest down and since.....and no one seems to have arrived at the crux to the often head-banging encountered. As mentioned above, it was only recently that the value of lead as a drier has come back to us. Small wonder but a careful reading of the historically-written shows lead as a favored drier well back to before the Renaissance; and this favor lasted well until just after mid-19th Century. And lead has been out pretty much ever since.
Yes, the answers are all out there and plainly available by a reading of the greater historical. But today, few appreciate the historical .... preferring instead to ask current and ever-changing Modern Science for its take in all matters. Myself, I'm just an oil painte r...and who today would take my opinion when a 'scientist' were available in the midst? Yet I sincerely, doggedly make the attempt....
It would be better that I wade into the matter slowly. Before I do, let me just say I do trust lead, manganese, and combined lead/manganese siccatives especially ; and I do use them in various forms and on a regular basis. I cannot but believe many of the olden painters also found good use for sics ... and that it caused no harm to the ultimate durability of their works.
Below is a small 'quicky' measuring 12x16" entitled "Gloam at Daybreak". It was painted once in a fast brush-work-y manner; then, after drying overnight, it was more carefully painted a second time. The first day I lubricated the white ground then began applying opaque coloring. No attempt was made to smooth brushwork ; any and all rugged brushwork was left as it came from the stiff hogs I prefer for quick painterly effects. During the process, the composition was developed and the whole was painted up to a generally vague, less defined manner. It all took just over an hour, though I came back later with a fresh eye in order to set in some slight balancing alterations. I used our Siccatif de Courtrai, both in my oiling-out medium (in this case, raw unrefined walnut oil with a few drops of the sic) as well as a droplet in each pile of color. This was done to push the solidification ('drying') of the paint --which it dependably did. The next day, the solidified and tack-free work was re-lubbed with the same oiling-out medium, then painted over again but with cooler tones this time; this cold over warm creating a bit of optical vibration. The roughed-in underpainting allowed some near recklessness in the overwork --such as 'brush-skip' in the tree-trunks, which generates the eye-charming effect of painterly-detail.
Manganese and Lead; Safe Paint ...Indeed
Umber is a historic pigment that, when made up into simple paint using typical oils (linseed, poppy, walnut), produces a very fast-drying substance that lasts quite well and is safe, though this somewhat depends on the oil utilized. Lead white is another such paint with a lasting ability --though, again, the oil is a consideration.
Both of these paints typically dry very fast due to their individually unique metallic constituents, which are lead in the lead white, and a natural dissolved form of manganese in the umber. Because they are drying, these paints can share their drying abilities with other paints. A bit of either one or both of these inherently fast-drying paints added to other slow-drying paints will speed the drying of the whole. [There are other traditional paints that will also do this. Smalt, a pigment containing slight amounts of cobalt, is said to be one ; and another is any copper-based pigment, such as verdigris. However, I shall remain focused only upon the lead and manganese herein. Also, no consideration will be made herein of the ancient copperas-- zinc sulphate-- which was said to be very drying in several of the old formulae.]
[An important note to insert here: many artists tell me their lead white-- which they obtain in
commercial tubed-form-- is not fast-drying. Be aware, freshly made lead white -- that stuff made
with lead carbonate -- will generally allow drying in one or two days; and this depending on the
ability of the oil used in rubbing it all up (for instance, refined walnut oil is processed with an
additive to discourage that oil's polymerization-- meaning it will take a very long time to dry.
Not so the unrefined nut oil) . Know that tube paints are made with 'extras' that often wreak
havoc to the natural and individual qualities of pigments. I advise all to make their own paints
when possible. Your work will be brighter and likely last better if you do; and especially so if
you use un-refined walnut oil as your binder.]
Painters (and other craftsmen) realized early on the drying abilities of these historically safe oil
paints, umber and lead white ; and they produced methodologies to put their inherent effects into
play. The simplest method to obtain the drying abilities of umber and lead was to cook up some
oil and include these metallic-based agents in the recipe. There was a slight problem
encountered. As mentioned above, the resulting oils created were often very dark; but -- the good
news -- only a small amount of the drier was actually and effectively needed to produce an
amazing drying effect. Another consideration: since lead white ground in basic unrefined oil was
already a fast-drying paint, and, quite appropriately, since most all the lights would require
some lead white in their mixture, there was really no major need to incorporate the dark drying
substance in the "lights" in order to hasten drying. Thus, we uncover in the olden writings the
typical advice to add the dark "drier" to the dark colors--like any of the carbon blacks; also,
typically, asphaltum (a never-drying paint). [ According to the old manuscripts, another
traditional drying-agent added to artist's oil paint was oil varnish. Regardless of today's 'modern'
science's in-ability to detect such varnish in the olden paint chips, this practice was documented
as early as the 1400's --see the Strasbourg Manuscript, wherein artists were instructed to make
their paint with oil and pigment ; but before painting began, a tempering of one,or-more,
droplets of an oil-varnish was directed. Such a slight varnish addition would engender
toughness, gloss, better drying ....and the frequent finding of "heat-bodied oil" in modern day
paint-chip analysis of the olden master-works.]
Clearly, powerful driers have been available to artists for many centuries. I have found recipe for making oil paint driers using umber and forms of lead very similar to Siccatif de Courtrai as early as the 1600's.
Here is a known recipe found in the 1635 Brussels Manuscript written by Pierre Lebrun:
" 23. Drying-oil is made by putting some nut oil into a pipkin into which is put a rag containing umber and minium [red lead pigment (JCG)], which is suspended to the handle of the pipkin, and then boiled."
This certainly sounds like a siccative in the same general realm as Courtrai Siccatif. One might think this drying oil could have been a weaker substance than Siccatif de Courtrai, but, realize (and try it yourself if you like), when umber is cooked into an oil --even without addition of lead-- a very dark brown oil is the result. Such a dark oil would never be mixed with various lighter colors in any great amount, otherwise, the color would be tainted. Thus, only a drop or two would be allowed in such lights. And so I might reasonably conclude the darkened 'drying oil' made with umber and minium must have been rather powerful in its effect.
Was this the first notice of using pigments to create drying oils? No. Giorgeo Vasari writing a hundred years earlier mentioned "John of Bruges [Van Eyck -JCG], a painter much esteemed in Flanders, set himself to try various kinds of colours and different oils to make varnishes." [There are those who dismiss Vasari's account of VE for various reasons, but I have never found any cause to doubt it. Irregardless such suspicions, the fact that Vasari wrote of cooking oils with colors shows it was a practice known to himself. As there are only so many colors one might use to give drying effects to an oil (or varnish), one can easily suspect the early painters would have tried umber (high in manganese) and lead white (lead).]
And so, taking Lebrun's recording alone, there is at least 400 years of use for a manganese and lead drier. And, believe me, driers would have been valuable agents for commercial oil painters plying their trade and meeting deadlines.
Another example: Rubens very likely used a drier with his paint as his work was said to be dry
and ready for shipment (rolled up no less!) within a few days of finishing. This makes perfect
sense. You see, any use of the usual slow-drying darks, i.e., like any carbon black, would
necessarily require such drying-help. BTW, this fast-drying info comes from a letter sent by the
master himself to one Sir Dudley Carleton, mentioning he had finished retouching the works on
the 28th of May and they were shipped on the first of June, 1618. [Note: caution should follow in
such deduction, for Rubens was also in habit of placing freshly painted works in direct sunlight
to help their thorough drying -- and age-old practice that greatly speeds the solidification of oil
paint. Then again, he advises De Mayerne to make a fast-drying varnish for coating finished
works by sunning oil (walnut? linseed? poppy?) with an amount of Litharge, which is, of course, another form of
lead (lead monoxide). Also note: A careful examination of DeMayerne's words points to this
concocted drying oil then being used, not alone, but WITH a common "painters' spirit-type
Time passed and during the 18th and 19th centuries, attempts to make commercial paints and
varnishes dry effectively caused the growth of the driers industry. Establishments sprung up
whose sole purpose was to make driers for the varnish/painting trade. The old knowledge of
using umber and lead oxides to create driers was slightly altered as various manganese oxides
and compounds became readily available.
Many countries had a driers industry. The driers themselves were somewhat secret in their
formulation. Still, most were essentially the same thing with small variance. In some cases,
resins as well as oils were also cooked into the driers to give certain desirable side effects.
Professional oil painters have always valued fast-drying paint so that their occupational output might be speeded up. Adding small amounts of commonly-available oil varnishes and "drying oils" would do a very effective job of speeding the dry-time. It would seem the town of Courtrai in Belgium was an early known site producing a good and fast drier; hence, "Siccatif de Courtrai" or "Courtrai Siccatif". S de C was made available to painters at the Victorian color shops; and it, too, became popular among the ranks.
Realize, S de C was a dark-colored drier. Aside from its metallic and other components, it was
given a turpentine additive as a carrier. Still, darkness aside, only a small drop was needed for
the job intended. But due to the turpentine carrier, as Vibert warned, some painters likely did
thin their thick paint with the drier -- a foolish practice which could cause some undesirable side
effects. [Be aware, everything in oil painting should be done in moderation. Too much oil in
your paint is a bad thing. Too much pigment/not enough oil in your paint is a bad thing. Too
much varnish added is a bad thing. And on...and on.... ]
Lead was often faulted as a "progressive drier" in the later 19th and 20th Centuries. What this means is, once the paint film is dry, the drying effect doesn't stop but rather continues and eventually completely oxidizes the paint into veritable powder. When cobalt became popular as a drier, manganese was also condemned as a progressive drier. And so, by about 1920, two of history's best metallic driers were being totally ignored by oil painters seeking safe longevity in their work.
I have read such warnings again and again but, in my own experience, have found no indication of this progression. Some wise-men say the work will seem fine for many years but then disaster will certainly come. There's no basis in history for such reasoning ; instead, it is an argument put forth when no other recourse is available. The fact is, if your work is fine after a month, then it shall likely be fine after a year. If fine after a year, it shall likely remain fine for five. And if fine for five years, well, things look pretty good & you've done your job well.
And so, is there any truth in the notion that these metallic driers are "progressive"? On the
contrary, my own applied tests--coupled with historical review of other's works -- show safe and
lasting results ; and especially so when, and I will underline here, the drier is used with walnut or
poppy-based paint; and this use, of course, combined with a basic understanding of lasting oil
painting technique. By comparison to walnut/poppy oil-use, without due caution, this Courtrai
Siccatif induces noticeable problems when added to linseed-based oil paint.
What are these problems with linseed based paint? The answer is yellowing and wrinkling.
Like as with the oil varnishes, the fault is not from the siccatif! The fault is inherent to linseed
oil. Linseed is one oil that certainly does seem to seek air (oxygen) in order to solidify. I say
this because linseed oil 'dries' upon its surface first, leaving what is beneath the solidified top in
a still-fluid 'wet' condition (this effect causes some experts to think regular linseed oil dries
faster than an equally-aged and unrefined walnut oil ). The outer dried layer then obviously
prohibits oxygen from reaching the underlayers. This inherent 'surface-drying' nature of linseed
oil can cause trouble. Most noticeable is a tendency to induce surface wrinkling; and this is due
to the surface drying (it's actually expanding over the still-wet underneath) of the linseed-oil
pellicle. This wrinkling is especially observable when linseed-based paint is applied in any
appreciable paint-thickness (in other words, when using this siccatif with linseed-based paint,
care must be taken to paint thinly. No thick impasto and no oily paint! Realize, any wrinkling
which would normally happen with linseed-based paint, were it allowed to dry at its own normal
rate, will now happen much faster and produce greater physical effects/defects. In precise
words, if the siccatif-treated paint is applied in anything resembling a thickness, or if that paint
is overbound with the linseed, the critter will wrinkle but good ).
There is another problem especially found with linseed-based paint. This is the easily-observed
yellowing that comes on once the linseed reaches a certain stage of drying. As example, mix up
some decent pure (and unadulterated with zinc/titanium) lead carbonate with linseed oil. Use a
minimum of oil and create a thick paste. Place the sample in normal room lighting and wait
three weeks. The lead white paint will have become noticeably yellowed. This does not happen
if walnut or poppy were used. This yellowing is just a natural side-effect of linseed oil. BTW, in
the future -- about 15 + years-- the yellowing will visibly subside as the thin pellicle of linseed
oxidizes away leaving the pigment exposed. [Due to this gradual reversal, oil painters are told to
not worry about the sallowing effect of linseed. But I must wonder over this advice ; after all,
who among us would wish to wait 15 or more years for their completed works to lose their
linseed-generated gallery tone? Not this one. And, BTW, if you've taken the care to varnish the
work, that varnish lock-up will stop the natural oxidation of the linseed pellicle...meaning it will
remain sallow indefinitely. Sure, you can bleach it in sunlight, but what buyer of your work will
be doing that?]
And so what happens when linseed-based paint is prod by a siccatif? It reaches its latent yellowing stage far quicker. In such case, the linseed-based lead white is seen to quickly yellow. The result being, the siccatif is faulted It is labeled the culprit and is said to have caused the yellowing. Not so; the siccatif merely brings out the inherent faults in the linseed oil. [Additional: some siccatifs are actually made using linseed oil, and so, be aware such sics will also yellow/brown in-and-of-themselves quite nicely.
You don't think linseed oil eventually oxidizes away? Yes, it does-- as do all the painting oils. Without the added durability of, say, a resin oil varnish, pure linseed or other oils are soft and gummy critters. Hot, and even 'cold' sunlight will speed this oxidation. But things like carbonic acid within normal air attack the dried oil films indoors, too.
Yes, it does happen. There are historical writings that mention this was a known feature of oil
painting. For instance, this oxidation was noticeable and written about as early as the 1700's
(mentioned page CXLV in Merrifield's book). Researchers today have again become aware of it
since the practice of covering oil paintings with glass was begun in the 1960's. What happened
was, the oxidizing of the oils used in the paintings soon produced a visible fogginess upon the
inside of the glass. In time, the fog will actually become colorized as the evaporating oil carries
micro-amounts of the variously-used color pigments with it. As a simple review of historical
paints and finishes applied to utilitarian objects (like cars and carriages) shows, the best way to
stop this oxidation is to add a resin oil varnish to the paint. Even an oil varnish made of nothing
more than pine resin cooked thoroughly into oil will greatly resist normal oxidation. Of course,
amber and copal oil varnishes are well-known oil film-tougheners --substances that provide great
resistance to the effects of oxidation upon the soft oils. However, realize, if the oil varnish is
made with linseed oil, or (and more importantly) if the oil varnish is used with linseed-based
paint, the yellowing nature of the linseed oil will remain visible upon the surface of the painting
for a much, much longer time-period. Again, this is simply the nature of linseed oil. The linseed
oil is the culprit. Walnut-based paint will not suffer the same fate. But the experts blame the oil
varnish or the siccatif.
Historical Use of Siccatifs
There were several siccatifs available by mid 19th C. Most known, Siccatif de Courtrai drier was
popular amongst the masters of the later 19th C. For typical use, a few drops were either added
to the medium in the dipper cup on the palette, or a single scant droplet of the pure siccatif was
mixed into the paint before use. Again, this siccatif does not bring out any additional latent
effect of yellowing when used with walnut/poppy oil-based paint. The poppy and walnut oils
will not yellow any more than they normally would (which, in typical room lighting, is
William Bouguereau and other painters used this drier to speed the completion of their work. It
is certainly helpful/advantageous to have one's preliminary work dry and ready for overpainting
on the morrow. For such purposes, few agents could match the ability of Siccatif de Courtrai.
Bear in mind, no harmful effects directly traced or attributed to this siccatif-use have been found
generally in B's work. Of course, some may think this surprising. It shouldn't be, for an
examination of B's painting methodology shows he favored painting with poppy and walnut oil--
not linseed oil; where the nature of that particular oil -- i.e., surface drying/tendency to wrinkle
when painted out thickly, and yellowing when a certain drying stage is reached -- presents a
detriment, especially to a thickly-applied technique (also, B was not known for painting with
Note: Regarding Bouguereau, like all painters, he was likely to have tried (or been forced to use)
linseed oil-based colors on some occasions. But his advice clearly favors the walnut and poppy
oils as his general means of creation. As reference, here is an historical attribution from a
William R. Laidlay writes in his book "Art, Artists and Landscape Painting" page 83:
"To my certain knowledge, Bouguereau used to work with Siccatif de Courtrai, which is said to
be a species of Japan; but be that as it may, I believe it to be quite permanent, and certainly most
useful in dark passages where much garance or other slow-drying colours are used."
Laidlay continues: "I may add that pictures I painted with Siccatif de Courtrai twenty-five years ago, have not changed in any way. Of course the siccatif is not used pure, but merely a few drops put into a dipper, with poppy oil and turps; and equally of course, no one should use any quick-drying varnish or siccatif , unless the foundation he is painting on is thin, and absolutely dry. Cracks and stars and all that sort of thing, proceed from using a quick-drying medium over a coat of half dry or slow-drying paint."
Laidlay's advice as to how the siccative is used is on target. I will tell you this: NEVER put a
fast-drying layer of paint over a slow-drying one. [ Mayer's book preaches the direct opposite
advice. He says siccatives have their better use in the final layers, like overpaintings and
scumbles, glazes. By contrast, Doerner gets it right, saying the better use is in the initial stages
(underpainting), but he essentially condemns all use of siccatives. Importantly, neither fellow
notes the important relevance to the type of oil being used ...nor does anyone else I've come
across today.] As a safe rule, I believe it is perfectly all right to use siccative in the same spare
but effective amounts in all layers. When impasto is desired, remember it is best to use a
walnut-based paint and do make certain the thick paint is rubbed-up very lean to begin with.
Too much of any oil is inviting problems when using thickly-applied paint layers.
The reader will please note Laidlay's mention of poppy oil and not linseed oil as his choice of medium. If I might add here, the use of an unrefined walnut oil is likely even better. BUT (!), never use refined walnut oil, as it is given a 'healthy' dose of a non-drying substance, likely soya vitamin E, at manufacture to actually slow or stop it from polymerizing (drying) ; and so as to make the oil remain edible longer. Thus, refined walnut oil was never meant to be used as a painting oil. Unfortunately, the refined product made for cooking/eating is today very cheaply available, allowing it to have become so-greatly used by today's paint-makers who do not understand it's inherent too-slow-drying fault ( BTW, most linseed oil is also made using a refining process today ; however, since most refined linseed oil is meant only for painting/coatings/compounds requiring expedient drying, there is no attempt to stop or slow its drying ability by addition of non-drying agents).
[ Whether your WNO has vitamin E added can sometimes be ascertained by checking the back label on the bottle/container. Usually, a darker color and some sediment at the bottom is a proper indication the WNO is the good raw unrefined product. Buy the unrefined product and use it in confidence. By-the-way, the paint makers using walnut oil today likely incorporate the cheaply-available soy-treated refined nut oil. From personal experience, I can easily predict no other downside to such use, other than the slow-drying character. In that regard, whether or not you've obtained oil paint made with the refned or the unrefined, the drying character can be easily remedied/speeded by simply adding a drop of Siccatif de Courtrai.]
Note on "through" driers:
Some today say driers can be divided into two distinct categories. They say there are "through" driers and "surface" driers. In this realm of consideration, lead is recognized as a 'through' drier. And cobalt and manganese are termed 'surface' driers. But be aware, these 'surface' and 'through' considerations apply to industrial varnish and other coatings typically sprayed thinly onto surfaces. As regards oil painting -- where impasto and a variety of other thick/thin-applications and glazes and scumbles come into play -- there is no justification I've found for such drier descriptives. [ For instance, lead carbonate is a pure lead and will cause drying of oils it is compounded with ; but this will not stop such paint applied in a thick pastose manner from surface wrinkling -- especially when linseed oil is involved.]
With oil painting, considering the variety of paint applications, the nature of the drying character
as regards 'through' or 'surface', happens pretty much according to the nature of the oil being used
for the paint. Walnut oil does indeed become 'dry' more or less throughout its whole -- this
occurring upon the surface as well as beneath the surface. By comparison, linseed oil will 'dry'
or polymerize to solidity preliminarily upon its surface, leading many to conclude linseed is the
faster dryer between the two oils ; and this while, underneath, the linseed-based paint is still
perfectly fluid -- and can remain so for great time-lengths. In extreme cases, the underlying oil, shut
off from air by the hardened pellicle covering, never truly solidifies -- as in some of A.P. Ryder's
19th C. works. By comparison, when the walnut oil paint is dry upon its surface, it is also fairly
well along in polymerization beneath its surface. Thus, walnut oil's almost plastic-like ability to
dry throughout allows impasto effects to be had with the better safety ; whereas wrinkling will
often result if using the linseed-based paint instead. Besides walnut, other 'through' drying oils
with historical use in oil painting are sunflower and poppy.
Regardless its 'through' or 'surface' nature, a drier generally compounds an oil's inherent natural
character. Again, the drier promotes polymerization/solidification of the oil. The nature of the
oil determines how it will solidify; either upon its surface or throughout its whole.
James C. Groves,
Frostburg, Maryland, September, 2002 ; updated: additional image/text supplied, February, 2003
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