iron oxide yellow

Ingredients

iron oxide yellow, goethite, egg yolk, egg white, gum

Preparation Steps

Original Recipe Text

Red, yellow and purple-brown ochres were the source of every red, yellow and purple-brown pigment tested in Northern Nigerian Qurɱānic decoration (p. 11). Yellow ochres contain goethite (p. 11). Biuret tests indicate the possible use of egg yolk or egg white as a binder, which may have initially intensified the yellow color in an organic dye (p. 10).

Evidence

"Microscopic examination of opaque yellow pigments revealed iron oxide yellow and tested positive for iron with potassium ferrocyanide... Biuret tests on glossy yellow ink flakes yield one positive for protein, indicating the possible use of egg yolk or egg white as a pigment binder since animal glues were not traditionally used in Northern Nigeria."

Remarks

Organic yellow dyes were also identified by their stain-like appearance (p. 10). Curcuma (turmeric) was also used, producing a bright yellow-brown mucilage that became tacky when exposed to moisture (p. 18).