I found this at web , article from 1895.
There are three processes in crystoleum painting fixing, preparing, and painting by which anybody without artistic knowledge is enabled to produce life-like pictures which are wonderfully effective, and which have all the delicate tints we see in ivory paintings.
The method is as follows: You have two convex glasses, the small oval or square size -will do for a small portrait, and it is best for beginners to try a small vignette first. When...