The number-one rule for keeping Oil Colours as good as new inside the tube is simple: recap the tube meticulously!
Once the colour is out of the tube and on the palette, oxidation of the linseed oil — or whichever oil is used — begins.
This means that fast-drying Oil Colours will actually begin to dry on the palette. Slow-drying colours will not dry as quickly, but oxidation will nevertheless have begun. Keep this in mind when working.
As a general rule, higher room temperatures will soften Oil Colours, while lower temperatures will stiffen them, to a greater or lesser degree.
