BLACK OAK BARK (Quercus nigra, Q. quercitron): Spreading tree native to Asia, Brazil, China, Japan, North America, Portugal, Spain, Mexico, Europe, Mid-East and the Mediterranean.
Dye chemical: quercitin. This is a much more reliable bright yellow than weld. African dyers used oak bark around 900 BC; the Chippewa and Navajo used it by at least 565 AD but though black oaks grow in Europe, there are no early records of dye use. Lighter on cotton than on wool and silk, very light-fast and wash-fast.
The beautiful yellow was also used as a medieval illumination pigment. AKA: Quercitron, yellow-barked oak [USA]
Alum mordant: stunning clear yellow similar to weld dye
Copper mordant: drab yellow-green
Iron mordant: olive green
Tin mordant: bright yellow