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Hard Copal for Mediums and Varnishes

This is hard copal, and is not soluble in gum spirits of turpentine. The material must be fused, in order to be cooked into a drying oil. The image above is of copal in its unproecessed state (right). On the left, and much darker in appearance is the same copal that has been fused. The one on the left is ready for further processing, in order to combine with linseed oil.

Hard copals are really no harder than soft or or recent copals, when using Moh's hardness scale. The difference is in the level of polymerization, and the resulting necessity of various methods of processing. Hard copals require a greater degree of processing, in order to make them into viable art materials. Much of what is presently available (copal mediums) are made from soft copals, and I don't think that these materials are the same as those used by artists in previous centuries. Hard copals are exceptionally difficult to process, and then even more difficult to subsequently combine with a drying oil, to form varnishes, and or mediums. Taubes method is very useful, yet without an added step, not mentioned in his book, it remains a very difficult proposition. If not completed just right, one will end up with a turbid mass, or a pot of ash.

I personally would not use any copal mediums, in my artwork that are light, and made with recent copal resins. Due to several reasons, the best varieties of hard copals are no longer available, and any of the resulting mediums and varnishes that I would buy, are no longer being produced.

Gum Elemi, used as a Medium.

This series of posts was completed for artist Graydon Parrish, to assist with his lecture on a particular painting (William Bouguereau's Nymphs and Satyr) as completed by William Bouguereau (http://grandcentralatelier.blogspot.com/2012/03/graydon-parrish-to-lecture-at-clark.html). It is a description of this material, and the reasons for its use. Nothing in these posts is an encouragement of others to make or use this medium, and is stated merely as a description of the material, and how I have made it.

It is a known fact that William Bouguereau used elemi, and copal in his work. In the world of art, and more specifically, oil painting, there have always been mediums, used for various effects. I don't wish to enter into debate with those who believe that all effects known to oil painting, can be accomplished with just drying oil alone. Although I do respect the opinions of others. I do not believe this, and in experimenting with many different mediums, have found that some provide effects that oil alone will not accomplish. Amber, copal, and many others.

Gum elemi has been of interest to me, for quite a few years. Years ago, at the Toledo Museum of Art, I had the opportunity to study a painting by William Bouguereau. I noticed that the surface of the paint film was absolutely smooth. No raised spots or even brush strokes visible. The image was of a girl, and all of the edges were fused. The image created an effect of being more real, than a photo. Based my observation, I became convinced that something more than oil paint alone was used to create the work. A bit of research led to an understanding that copal and elemi was used by that artist, as a medium. This led to experimentation with elemi, and although I have never come close to creating a work, such as that artist, I have noticed that the mediums which contain copal and elemi permit some comparable effects.

Gum elemi derives from trees in the Phillipines, Southeast Asia, and other locations in the tropics. It is a balsam, although cloudy in appearance, and not at all like the other balsams, upon initial consideration.

It was used in the past as a plasticizer for varnishes, as it was known to remain flexible, and this can be beneficial, to prevent cracking to crystalline varnishes applied over an oil film.

Used as a medium, elemi would be of no use by itself, as it is initially too viscous, and would not impart any benefit to oil paint, in its raw state. Once processed however, I have found that this material imparts some quite impressive effects. In using it as a medium, the plasticizer effect is helpful, but there is an additional effect of permitting paint to tack up while remaining wet, and I don't think that anything provides a better blending effect. Although Canada balsam, and Venice turpentine permit paint to blend quite well, gum elemi surpasses them, in my opinion.

Bouguereau used various mediums in creating his work, and it is known that he combined gum elemi, with hard copal medium. This medium is quite impressive, in that it permits all of the effects of copal, while allowing for a better blending effect, is thinner initially, and again, acts as a plasticizer.

The picture above is gum elemi in its unprocessed form. It is very viscous, and yet will flow very very slowly over time.

Gum Elemi used as a Medium 2

Unprocessed gum elemi. Very viscous, and will hold a palette knife that is stuck into it.

I have cut out a piece of the elemi, and you can see the debris that is contained in it. It is very thick, and sticky, and very fragrant. I don't agree with Doerner who stated that it smells like fennel. Rather, it has a unique smell, and I like it.

This is another closer image of the elemi. I will be placing it in the jar depicted. I prefer to use old pimento jars for my mediums, as they are not deep, and permit easy extraction of liquids.

In this picture, I have added gum spirits of turpentine to the jar as well. The turpentine is artist quality, and I avoid the use of the nasty smelling hardware store material, that I call gagamaggotine.

This is a photo of a jar of gum elemi, mixed with gum spirits of turpentine, and one can observe the clear material at the top, and the sediment that forms on the bottom.

This is the gum elemi mixed with gum spitits of turpentine. It is starting to get cloudy as the elemi dissolves in the solvent.

A little while later, and a little more cloudy. This will dissolve down to its saturation point. That is where no more resin can be accepted by the solvent, and then the remainder will stay in an undissolved form. I like to go by the saturation point as a reference point.

The resin is a component of the entire material. I dissolve the raw material in gum spirits of turpentine, thus liberating the resin from the waxy material and debris, which remains at the bottom of the jar. The resin in the turp is clear as water. At that point, I add a little more raw elemi, and watch it over a day. It will continue to dissolve, and when no more of the lump goes down, it is at a saturation point. I wait till fully settled, and clear, then remove carefully, with eye dropper. I then combine 50/50 with hard copal medium. Very little will alter the properties of paint.

This material will remain cloudy for several days, and then will clear. The turpentine will solve the resin, and a waxy sediment will form, on the bottom of the jar. The debris will remain with the sediment. This sediment can still retain some unsolved resin, and I won't go into detail about my exact process, but the material that is on top is absolutely clear, and to my eye refracts light to a greater extent than water, as it magnifies images through the glass, moreso than other materials. I would further add that the material is as liquid as gum spirits of turpentine.

I remove this material very carefully with an eye dropper, to avoid stirring up the sediment.

This is a picture of the elemi that has been removed from the jar. It is very clear, and thin, in its nature.

Another picture of the elemi. I store this material in 30 ml. bottles, and have found these quite useful.

In this state, the material can faciliate the manufacture of copal mediums, as it acts as a thinner, yet jacks up the resin content, all the while, acting as a plasticizer, and permitting effects that copal alone does not. It also seems to speed up the drying of oil paint.

Although very thin, once the turpentine evaporates off, a highly sticky residue remains. This residue provides the benefit to paint, in my opinion.

This is a small jar of copal medium that I made last year. It is hard copal that has been fused, processed further, and then cooked into linseed oil. This is an excellent medium, for a variety of uses.

These are the two materials that I will combine, to create a copal/elemi medium. The copal has a resin content of approximately 25% resin to linseed oil.

The copal is from Kremer, and is a hard copal. This doesn't mean that on Moh's scale it is any harder than a soft resin, such as damar, or manila copal. Rather, it must be fused before it can be made into a medium. Fusing hard resins is difficult, and dangerous, and I would not encourage anyone to try it. The copal is actually quite a bit more difficult than even amber to fuse, and make into a medium, as it is very difficult to effectively combine with linseed oil. Amber is much easier. If not done right, one ends up with an unusable mass that resembles snot. A turbid disaster. There are also serious dangers regarding the heat needed to process this material.

In this picture, I have a small amout of copal medium, on a palette knife. I will place this on the glass plate.

This is the copal medium, placed on the glass plate. I would add that although darker than linseed oil by itself, it doesn't alter the color of oil paints, to any noticeable degree, in my experience.

In this picture, I have removed a small amount of elemi/turpentine solution, with a small eye dropper.

In this picture, I have added an equal volume of the elemi/turpentine solution, to the copal medium, that was placed on the glass plate.

I next mixed the elemi/turpentine, with the copal, and used a small palette knife to accomplish this. I call this medium: Bouguereau Medium.

I then placed several same size nuts of ivory black oil paint, made by Liquitex, and comparable piles of titanium white oil paint, that I made last year, onto a paper palette. Next I added a drop of the medium to one piles of black, and one pile of white.

Next using two of the same brushes, I quickly mixed the oil paint that was without the medium; just oil paint alone (as depicted on the left).

Then using a clean brush of the exact same type, I mixed the black and white paints which contained the small amount of elemi/copal medium, together, very rapidly, using the same strokes. This is depicted on the right.

The paints were the same (type/amount), the brushes were the same, and the strokes were the same, but the paint with the elemi/copal blended much better. It blended with a great amount of ease. Although certainly not scientific, and for all intents and purposes a quick and dirty demo, it should illustrate my point. Just two drops dramatically alter the paint.

Although oil paint alone is known for its blending properties, and copal has some great effects, the elemi, permits a blending that is so easy, it almost does it for you. It is a pleasure to work with, and permits a paint film that has a super sfumato effect. One can easily obscure all edges, and then come back and add some hard, wherever they want, for contrast; with great eases. The elemi also thins out the ultimate medium, so that it is thinner than those containing Venice turpentine, or Canada balsam. The colors just go right into each other. The paint alone does blend, and could be blended further, but the effect would not be the same. With the same strokes, one just goes together, and in the other image, the paints maintain their individual value properties, to a greater extent.

Obviously, this medium would not be good, if a more impasto, painterly approach is desired.

I would further add that this medium permits a very smooth level surface, to a larger extent than even the other balsams do.

At one point I got some of the turpentine containing elemi on my fingers, and it felt no different than regular turpentine, until the turp evaporated. My fingers stuck together. This illustrates why I think it should be combined with an oil, and shouldn't be added directly to paint.
A couple of weeks ago, I combined the elemi in a 50/50 mix with a good quality stand oil, as I wanted to see it copal was necessary. In effect see how this performs. Since stand oil is commonly thinned with turp, and it does have properties that are similar to mediums containing hard resins, I thought that the elemi may approximate the effects of copal, and thus make the copal medium redundant. The stand oil is very tough and flexible as is, and the elemi will provide a measure of flexibility, and grab. Also, since the medium is crystal clrea, it won't change colors at all. I haven't tried this Elemi/Stand Oil Medium yet, but will be doing so soon. Fingers crossed!

I have never known of any elemi mediums to be available for sale, anywhere since I have been involved with painting, over the past 20 years. Obviously gum elemi is still available, and there are materials for sealing wood etc., yet I don't know of any elemi mediums being sold as such (i.e. a medium to create soft flesh tones, a well blended effect, an level surface, and for any and all of the properties that the material gum elemi imparts). Even in times gone by, I suspect that artists such as Bouguereau (being quite creative, and fully aware of materials) combined materials, and made these things themselves. I have worked hard for years to develop these ideas and mediums. Much trial and error.

Best regards, Jim Trankina