Gofun is a kind of pigment. Now it refers to pigments which are made from shells and consist primarily of calcium carbonate. It is called Gofun (胡粉) because it was brought from Ko (胡) which meant the western part of China before. It referred white lead (lead carbonate basic) in ancient times. It is used to color Japanese paintings and dolls.
Clamshells are used to realize a higher whiteness degree, but materials like oyster and scallop shells are also used because they work easily. The shellfishes are the same as those eaten, but shells with a higher whiteness degree are searched from all over the country.
Process for making
Expose shells to the sun for a period of between a few months and decades until weathered. Therefore it is longer for hard shells such as clamshells. Crush shells after exposure to the sun, mix it with water to make it clayey, roll it out on a board and completed after exposing to the sun again.