The fattest medium, Art Spectrum Medium No. 3 is a thicker, slower-drying medium than Art Spectrum Paint Medium No. 2. It is for painters who like a heavier, more viscous, medium. It is ideal for artists who paint in many layers. The artist begins with Art Spectrum Medium No. 1, then uses Medium No. 2, then finally Medium No. 3
Art Spectrum Medium No. 2 may also be thickened incrementally by adding Medium No. 3 in 10 percent increments.