amount of medium and cracking

I am looking forward to buying Geneva oils when they become available again in the UK, as I like that they are fluid. In the meantime, I have been premixing my own using the slow dry recipe.

However, I have read that use of medium should be kept to a minimum, as tubed paint is usually at an optimal pigment-to-oil ratio that when deviated too much from, increases the chance of problems such as cracking, wrinkling or yellowing. For example see the section called 'Use as Little Medium as Possible' here:

I personally don't like how thick oil paint is out of the tube. Even more fluid brands like Rembrandt are too tacky. 

I like paint that flows off the brush easily, hence why I mostly use acrylics (which by the way I find is a gorgeous medium). And this is also why I really like the look of Geneva oils.

But I'd value the opinion of more experienced artists on the issue I discussed above - thanks!


  • Hi @frva – since different brands of oil paints are very different viscosities out of the tube, there seems to be a missing piece to this puzzle. Not all brands of paints are the optimum pigment-to-oil ratio. This is a goal, not a given or even commercial standard. The thicker paint often has fillers and extenders in it, which changes the viscosity without changing the “pigment.”

    If you add no more than 20% additional oil (or alkyd or whatever you use) to the paint nut, and if you do not paint in a heavy impasto, I think you will not encounter any wrinkling.

    Here is a wonderful resource: MITRA is free and in English language: Resources (

    PS - the question you asked is one which provokes animated discussion and opinions. So, I always suggest finding an authoritative source of information, and not relying on opinion.  


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