Late Summer

A reader mentioned my excessive use of White Spirits solvent. His concern was the dulling effect on colours and the resultant weak paint layer, prone to cracking.  He gave a brief outline of his painting method and his particular attention to the ‘fat over lean’ principal. Very sound advice indeed if you paint in the strictly traditional method.

If Liquin or any Alkyd based media are used with traditional oils, adjustments have to be made to the working method. I will refer you to a recent post (here) regarding this medium.

With regard to White Spirits mixed with Linseed Oil or the other vegetable oils, this solvent does behave differently to Turpentine. The key issue is the viscosity of the two solvents. Viscosity is how ‘thick’ a liquid is.  Adding Turpentine to Linseed Oil lowers its viscosity, White Spirits lowers it much more. Traditionally prepared oil painting grounds are based on Linseed Oil / Turpentine absorption levels. Linseed Oil / White Spirits has a much lower viscosity and is drawn deeper into the ground carrying much of the Linseed Oil with it. The result is a dull, brittle paint layer liable to cracking. There is also the possibility of the canvas fibres penetrated by Linseed and this can cause other problems.

This is not all theoretical stuff as I noticed the difference when I stopped using Turpentine. I could not use many of the commercially available oil painting grounds, with White Spirits, as they appeared to be too absorbent. Switching to Alkyd Oils while using White Spirits was completely different – no ‘leeching’ of medium into the ground.

So why did I stop using Turpentine? Many years ago I gave classes in Oil Painting. While I didn’t have any problem with the vapour from Turpentine (I quite liked it in fact), many of the students did, getting headaches or skin rashes. We agreed to ban Turpentine from the classroom and use odourless thinners instead. Some time later Turpentine was classed as a toxic substance and since then I just never bothered using it. Odourless thinners is not always available here but White Spirits always seemed to be on the shelves of the art stores, so White Spirits it was.

Here is the painting of the above. See you soon.