Last Thursday evening I finished painting #4. Each one gets a little larger as I become more familiar with the handling and brushability of the paints. Unquestionably, these historic pigments are profoundly different from the modern ones. Paints without a wax binder or other stabilizers are "long", meaning slightly runny and not in any way creamy and fluffy like the modern "short" colors. Instead of staying in a tidy little lump, these spread into a puddle form.
They can become thin and transparent if too much medium is added too quickly; but, at the same time, can be gritty. One beautiful green earth called, epidot, is extremely gritty and after being squeezed from the tube turns to an impenetrable goo. The only possible way to use this color is immediately after it lands on the palette.