Platina Yellow is, as its name implies, a preparation from platina, which has afforded the author a series of yellow pigments, the deep of which resemble the Terra di Sienna (VIII.), but are warmer in tone and richer in colour and transparency, much resembling fine gall-stones, for which they are valuable substitutes. They work well, and are permanent both in water and oil, when carefully prepared; but any portion of palladium in the metal from which they are prepared neutralizes their colour, and renders them useless.