linseed oil

[kate252]

well folks- i hate to tell y'all but the olive oil painting has dried. yep- dry as a bone. (apart from the very thick parts- but the thin parts- which was heavily diluted with the oil is completely dry) However- i figure everyone would be using olive oil if it worked as its so much cheaper and they dont. although- i thought- in actual fact- the oilve oil was great to paint with.
however- ive decided to be on the safe side and ive bought linseed oil.
i just thought id let you know the outcome.

ive bought stand oil- which i believe is slower to dry- that suits me better. but wiki said it was thicker. to me it seemed the opposite- it seemed much thinner.

[Carcharhinus]

My stand oil is way thicker than my refined linseed, to the point where it's much more difficult to work with. It's more like honey, whereas my refined is like cooking oil.

[Jason1616]

I think you're wise to go with traditional linseed oil. It's been time tested for centuries and is known to make a stable paint film.

Olive oil has been around even longer...since the ancient Greeks at least, so I think if it made a good oil to paint with, people would have known that hundreds of years ago.

It's really not the linseed oil in paint that is expensive, it's the pigments. I would definitely stick with linseed oil from now on so you don't have any problems.

Jason

[libby2]

Walnut oil is one of the oils known to be used to adulterate olive oil, been going on for years. There have been a few scandals over the last 20 years. It's possible that you have a bottle of walnut oil and not olive oil.

Walnut Oil

Adulteration test

Olive Oil Adulteration / olive oil times.com

[sidbledsoe]

Howeve be using olive oil if it worked as its so much cheaper and they dontr- i figure everyone would.

Originally Posted by Jason1616

Olive oil has been around even longer...since the ancient Greeks at least, so I think if it made a good oil to paint with, people would have known that hundreds of years ago.

Without knowing any of the lipid chemistry behind the reason for this, you must trust trust your intuition, You and Jason are thinking correctly here, olive oil is not a good choice for usage in oil painting, it is a very bad choice.
Yes, let Rachel Ray use it in the kitchen instead. It does great there.
Kate why do you hate to tell us that it dried? I assume because you added some as a medium then saw that the drying was slowed and posted a thread and were told that it will not dry. That isn't the case as you saw, it is possible to add some to paints that are already made with good binding oils and eventually it may dry to the touch but the paint film will not be as good as it would be if you had used a proper binding oil for your medium.
You can sort of get away with adding a little but it will do nothing but harm. You will find no paints made with straight olive oil. Lipid chemistry is not easily understood but here is a brief summary of what is going on here. All oils are composed of mixtures of varying concentrations of fatty acids. Olive oil is mainly composed of oleic acid. There is a certain percentage of oleic acid in nearly all of the binding oils we use in paints. Even in linseed, walnut, and safflower oil you will have a small percentage of oleic acid. But they are mostly composed of linolenic and linoleic acid. These will oxidize and make good polymers that make good paint films. But what you added was a higher amount of oleic acid, which does not polymerize well.
It is all about the unsaturated double bonds present in the particular acids.
Linolenic has three of these bonds, think linseed oil, it dries fast and it makes a longer chain sturdy polymer.
Linoleic has two of these bonds, think walnut, safflower, etc. and they dry slower and make a bit shorter more brittle chain polymer, but they are also very acceptable.
but poor old Olive oil mainly has oleic acid and it doesn't cut it for drying or for making a good polymer chain. You can add some, but not too much, the more you add, the more it will compromise both the drying and the paint film integrity.