Q: Would you please explain the difference between a gum and a resin?
A: A gum is a dried sap from any number of trees and shrubs
found throughout the world. Some are soluble in water; others that
aren't will swell to many times their original volume when soaked in
water. Gums are typically used as binders for paints such as
transparent watercolor and gouache, as well as for tempera emulsions.
They're also used in the manufacture of adhesives, sizes, and
stiffeners. One common product used is gum arabic.
Resins are amorphous, transparent, or translucent solid organic
substances that are solid organic substances that are soluble in
volatile solvents, either cold or when melted. These solutions are used
as coating materials, such as varnishes, and as pigment binders. Resins
can be natural or synthetic, and differ from one another in such
properties as hardness, solubility, color, and odor.