Grumbacher - Gel - 5oz - Grumbacher Gel Medium is an Artists oil color medium that is colorless and compatible with all oil colors. Grumbacher Gel has the same consistency as oil colors fresh from the tube. Opaque oil colors properly mixed with GEL become transparent, but retain all the characteristics of hue, consistency and texture of the tube color. By itself, Gel Transparentizer dries very slowly, at about the same rate as Alizarin Crimson. When mixed with color, will retard the drying time of the original color. Can be mixed with any conventional oil painting medium or solvent. Can be mixed with color at any ratio.