Impasto Medium is an oil painting medium of finely ground calcite, silica and bentonite in pale linseed oil. Use it to extend paint without altering the consistency, making oil colors 'short' and buttery for impastos. Stiffer than Velázquez Medium, this putty-like medium makes colors slightly transparent while allowing you to build impasto, thick applications of paint. When added to oil paint, Impasto Medium does not alter its color temperature. It can be thinned with solvent or oil. Depending upon the proportion added to paint, Impasto Medium does not affect the drying time significantly.

Impasto Medium does not contain stearates, solvents, driers or natural or synthetic resins, so it is safe to add to oil paint without the worry of cracking or delaminating.