A. Some artists who use glue painting will spray a coat of alum/glue/water on a painting when the pigments, upon drying, have become powdery and lack adhesion due to too much water and not enough glue.
Can formaldehyde be used to remedy lack of adhesion of a paint layer ( due to a watery mixture with insufficient glue content ) ?
If so, how? By spraying it on as is from the bottle or mixing it with a glue water solution ?
B. Alum is used in the glue/water mix as a coating, functioning as a sealant and primer I believe, to prepare watercolor papers for glue painting.
Can formaldehyde replace the alum for this purpose ? Again, if this is possible, how should it be done ?
All of the best,