Roskruish and okhrenie are two terms a student of icons should know. They signify two steps in the painting of Russian icons.
Roskruish (роскрыш– also transliterated roskrysh) is the application of the flat, often dark base colors to the image. Here is a brief video showing that step in the painting of an Igorevskaya icon. You will note that the costume is painted before the faces. That is traditional. In old icon workshops with assembly line production, it was customary for the costumes and backgrounds to be painted by a different painter or painters than the one who did the faces. The face painter was generally more skilled — but of course in a small workshop it would all be done by one person.
Once the roskruish is completed, then the okhrenie (охрение) begins. Okhrenie is the application of lighter colors to the dark base color of the “flesh” areas (face, hands, etc.). It is essentially the process that creates the features of the face in paint, rather than just the preliminary drawing or pattern drawn or scratched into the surface of the icon panel (it was very common for Russian icons to have the outline of the pattern scratched into the levkas (gesso) surface of the wooden panel).
Here is the okhrenie of the Igorevskaya icon:
And here you see the continuation of the process:
These videos use the plav’ technique, in which the colors seem to melt into one another, rather than the otborka technique, which uses fine but clearly separate strokes of paint to lighten the dark background color and thus bring out features and highlights.