Natural Impasto Medium to extend paint
Impasto Medium is an oil painting medium of finely ground calcite, silica and bentonite in pale linseed oil. Use it to extend paint or pigments without altering the consistency. Stiffer than synthetic medium, this putty-like medium makes colours slightly transparent while allowing you to build up thicker applications of paint. When added to oil paint, Impasto Medium does not alter its colour temperature & can be thinned with natural oils. Depending upon the proportion added to paint, Impasto Medium does not affect the drying time that 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.