Very rare. A very important paint historically, found in frescoes from the 13th Century and then used widely throughout the Renaissance, to such a point it became known as the 'yellow of the old masters'.
The first thing you notice is it is a dense paint, it is exciting to see/feel different textures/densities in paint rather than the modern homegenous, fluffy, buttery, paint.
In masstone the hue is a delightful ocherous, muted, yellow, reasonably high in value for a paint classed as dark. It's colour is highly reminiscent of Titian's and Rembrandt's paintings.
It makes sense, given it's make up, that it is quite similar to Naples yellow in masstone but without the greenish cast. It is a gentle tinter and makes cool, gentle, muted yellows when mixed with white.
Historically accurate, authentic and an inspiration to use.
Technical Overview
Pigment - Lead Tin Oxide (Lead Stannate)
Opacity - Semi-Opaque
Binder - Linseed Oil
Tinting Strength - Low/Medium