Ware with yellow-staining black

This is a group of vessels from Nishapur decorated in black on a white engobe that Wilkinson treats separately because of a distinctive yellowish glaze, ranging from pale lemon to a strong transparent yellow, strongest near the black pigment, which tends to separate into specks. ¹ Pieces ascribed to Rayy in Pézard's book are, he thinks, probably from Nishapur. ¹

Wilkinson does not regard the colour as an accidental tint from carelessly prepared glaze; experiments for the Museum by the potter Maude Robinson showed the effect can be duplicated by introducing chromium oxide into a black. ¹ Other staining pigments occur at Nishapur, such as an olive green slip that yellows the glaze nearby, used on ware meant to resemble monochrome lustre and also used at Afrasiyab. ¹

Its body is like that of the colour-splashed and black on white wares, but some of its shapes are unknown in black on white and some black on white shapes are absent from it, so Wilkinson does not regard it as a by-product of the black on white potters. ¹ Its very glossy lead glaze, lemon or golden, may recall monochrome lustre ware, especially where its designs include birds. ¹