Shell palladium, so named as it used to be made and stored within shallow seashells such as clamshells, is genuine palladium powder finely ground to a pigment and bound with gum Arabic to form a solid watercolour block. Shell palladium is used just like watercolour pans, by first wetting the block with water to release the paint and then applying it with a soft-hair brush. When painting with shell palladium you can add a drop of ox gall to break the surface tension to improve the flow of the paint.
When dry it gives a finely grained matte finish that can be brightened up by burnishing the dry paint with an agate- or metal-headed burnishing tool in order to produce a vibrant shine.
This shell palladium
is supplied as a !!<¼>!! pan measure.