Greetings
I’d like to ask about black oil (leaded oil). I found somewhat contradicting informations about it.
Natural Pigments sells “Dark drying oil (Black oil)” and the description says:
Dark Drying Oil or black oil is a fast drying oil made by heating linseed oil with lead oxide (litharge) and used in historical oil painting. The lead (metal basis) content of our dark drying oil is about 3% by weight.Use
Black oil can improve the handling and drying of oils and can be used in recipes to make megilp, Maroger and Roberson’s mediums and traditional oil varnishes, such as copal.
I’m not interested in Maroger and Roberson mediums, or traditional oil varnishes, but the statement “Black oil can improve the handling and drying of oils” sounds intereseting to me. As far as I know certain lead compounds speed up drying of the paint film and/or increase its flexibility and durability. Thus, it would seem to be useful medium.
However in MITRA pdf article “Myths, FAQs, and Common Misconceptions”, there is this statement in the last chapter about Maroger mediums on page no. 11: “Dr. MarionMecklenberg of the Smithsonian Institute’s Museum Conservation Institute,however, has shown that paint films containing even small amounts of leaded oilare substantially weaker than those containing only cold pressed linseed oil.”
Of course I realize that the actual amount of black oil in medium/binder can have varying effect. But generally – how is it with black oil? Can it provide any advantages, e.g. better balanced through drying of paint film and increased durability, or not?
An aging test released on a pdf (was it by Mecklenburg I can’t remember) showed that a lead white bound with black oil progressed towards being too hard as the years passed. However it might seem a reasonable idea to add a little black oil to those pigmented colours with paint films tending to age too soft, such as the earth pigments. This is under the expectation though, that they aren’t going to be mixed on the palette or canvas with other colours that induced hardness themselves.
In a search for a general painting medium it doesn’t seem advisable to use black oil. I hardly ever use it myself.
Mark.
George, Mark, thank for your input.
I thought that adding a small amount of black oil to any pigment would be beneficial, like providing more balanced drying of paint film. I intended to premix a binder from refined linseed oil and black oil e.g. in ratio 90 – 95 % refined linseed oil + 5 – 10 % of black oil. But now I see, that there isn’t really any good reason to do it. I might rather try Rublev Japan drier eventually.
Black oil provides interesting behavior when added to oil paint. However, as was noted in studies, it does not improve the physical properties of oil paint films. It is an integral ingredient in several 18th and 19th centuries oleoresinous mediums such as megilp and Maroger.
