Ochres are Natural Yellow Iron Oxides with a slightly brown undertone.
Raw Siennas are unique shades of natural yellow with a brown undertone.
Synthetic Yellow Iron Oxides
Synthetic Yellow Iron Oxides are brighter and cleaner yellows than their natural counterparts. They have greenish to brownish undertones.
Blended Yellow Iron Oxides
Blended Yellow Iron Oxides are created in a full range of yellows by combining both natural and synthetic iron oxides. The properties of any given yellow are determined by the properties of its raw materials; they often utilize a certain performance characteristic of one of their components to enhance the quality of the overall blend.
Syn-Ox® HT-1000 Zinc Ferrite
Zinc Ferrite solves the problem of limited heat stability in natural and synthetic yellow iron oxides. In order to achieve an inexpensive yellow in applications requiring heat stability above 350 degrees Fahrenheit, Hoover Color Corporation combines yellow iron oxide and zinc oxide to produce a Zinc Ferrite compound. Hoover Color Corporation offers a single grade of Zinc Ferrite: HT-1000.