Finally got around to making my own paint using home refined oil 🙂
Plain curiosity had already been pushing me to try making my own paint for a while when I discovered Tad Spurgeon’s website a few years ago. He points out that a crucial difference between the quality of pre-industrial studio-made paint and modern tube paint is the quality of the oil being used.
Briefly, pre-industrial painting oils such as linseed were frequently refined in the studio following a fairly simple procedure involving water, sand and sometimes salt. Spurgeon’s extensive research (available in a book I whole-heartedly recommend to any painter) has shown that this type of oil exhibits a lot of desirable qualities not present in the commercial alternative. One of these qualities is the rheological (textural) properties of the oil when mixed with pigment.
The oil refining procedure deserves an entire post all to itself. For now, suffice it to say that the oil I used to make my paint was refined following Spurgeon’s ‘SRO’ (Salt-Refined-Organic) formula starting from pure unrefined organic cold-pressed linseed oil. The refined oil was then heated for 2 hours at 150°C, a process know as ‘heat-bodying’
Here is a quick overview of the paint-making process:
A muller and slab are the traditional tools used to make oil paint. The idea is that the rough glass (or stone) surfaces break the coarse pigment particles into a very fine powder. The pigments available today, however, have generally already been finely pulverized. In this case, the shearing action between the muller and slab breaks apart any clusters of pigment dust, ensuring a thorough mix.
The new oil performs much better than anything I’ve used before to make paint. As a comparison the following picture highlights the difference in texture between paint made with a commercially available heat-bodied oil and one made with the home-refined oil.
As you can see, there is a BIG difference in texture. The first paint may look like it simply contains too much oil. But this is as dry as I could make it.
I’ll still have to do more test to see how this paint holds up against high-quality tube paints, my guess is that it will be at least as good in terms of drying speed and probably better in terms of being non-yellowing. Film strength should also be superior but I haven’t thought up of a way of reliably testing that yet.
It turns out this paint performs pretty well right after being mulled but it slumps within 24 hours and returns to the consistency shown on the left in the last picture. Apparently this is normal behavior for handmade paint. In fact, paint was frequently made fresh daily by the artist or his assistants in the studio because of this. It is for this reason that most modern paint manufacturers add some sort of stabilizer to their tube paints.
Ideally, little or no stabilizer should be used in an artist‑grade paint. There are certain pigments, when ground into linseed or poppy oil, that could either have a stringy consistency or a tendency to separate from the oil. Such stabilizers as waxes (beeswax or aluminum stearate), water, and alumina hydrate (added to give bulk) are currently utilized to regulate consistency. Although there are definitely cases where it is more helpful than harmful to have small amounts of these additives, the use of these materials has been abused, particularly in lesser grades of oil paint. Since these ingredients can be use to give a desirable consistency to an otherwise inferior paint, one has to look for additional clues to determine the quality of a paint.
Excerpt from ART HARDWARE: The Definitive Guide to Artists’ Materials, by Steven Saitzyk © 1987 revised 1998
Tad Spurgeon mentions some techniques to obtain stable handmade paint using only oil and pigment but I have yet to have any significant success in this department (this involves the use of aged and heat-bodied home-refined oil which I do have but which might exhibit better working characteristics a few months/years from now). The search continues!