Originally Posted by Einion
I didn't twist anything above Karin. As we saw the other day perhaps you're just not reading carefully enough.
Could you answer the question I posed above please - which brands of oil paint use oil processed specifically for use in artists materials? You stated "if you buy artist's oil you know it's processed for artistical use." so, is this based on some evidence or is it merely supposition?
The oils used in mediums and paint in fine art painting, is the single most important factor to determine, among other things, how the paint will yellow over time. Since I know that the oil sold by producers of painting materials has a certain acceptable quality, I would not buy oil from hardware-store, food-stores or other places, sold for other purposes than fine art, if I am to use it as a painting medium. The oil is too important to fuss with.
Of course, if one doesn't bother about yellowing, or other properties of the oil, there is a lot of different liquids to mix into a painting, some of them sold in food-stores.
This was a comment to the general discussion in this thread. One of the posters in this thread has recommended the use of linseed from other sources than fine art paint manufacurers for use as a paint medium or as oil for making paint. He is wrong about that, imo, but I tried to say this in a polite manner, not to insult or attack in any way. The above mentioned poster has contributed to this thread in other valuable manners, and of course he doesn't mean to say something misleading or alike.
Normally, linseed oil isn't sold in food-stores. So yes, it's an assumption, that most of the produced linseed-oil is processed for house-painting, wood-work and artist's material, or alike.