To isolate a charcoal or chalk drawing from disturbance or use as a size for both the support and the drawing, this is a simple and effective recipe:

Ingredients:

Synthetic glue (white glue---1 part
Water---5 parts


Technical Procedures:

Take any white synthetic glue and dilute it with water. Add more water to make the solution spray easily, or brush it on as is. Where cloth, wood, or paper are to be sized, vigorously brush on the solution to be sure it completely penetrates the surface. Coat the back if it has not been penetrated by the size. If the surface has been drawn upon and you wish to preserve the drawing without smearing it, thin the mixture with water until it can be sprayed with an atomizer. The coat will dry within half an hour and can now be worked over with almost any kind of paint.

NOTE: In a pinch, a fine coat of hairspray will provide a sealing coat and can be used as a fixative.