O rganic or inorganic? Natural or synthetic? There are all possibilities on the market. The number of pigment indices is large and confusing. Not all pigments are equally suitable for all applications. This already results from the chemical basis and how the colour impression is created. Today, iron oxide is mostly produced synthetically, but it also occurs in nature in various shades. Yellow is FeO(OH) and is dehydrated by high temperatures above 200ºC to Fe , which is red. In the past, many chromates with a yellow hue were also used, but this has disappeared from the market for health ...