Yellowing

The greatest disadvantage of oil paint apart from very slow drying is the strong tendency of linseed oil to gradually turn yellow with age. Stand oil is the variety of linseed oil least prone to this, but it has other less desirable characteristics such as particularly slow drying, and its viscosity makes it more suited to glazing than general paint use. Some types of oil are sunbleached to reduce the color of the oil, but it seems that in the long run it ends up just as yellow as other types. For this reason it is desirable to minimise the addition of oil to paint. Some manufacturers replace linseed in light colors and blues with safflower oil to avoid this problem in sensitive colors. Some cheaper or poorly made papers are also prone to yellowing. Newsprint, the worst, will discolor within weeks. If it were only the color, then this could in many cases be desirable but unfortunately the yellowed paper also becomes brittle and loses strength. The best rag papers should not yellow, even after centuries.