Description: Slightly acid mordant of white powder or silver-gray metallic granules with 4.5 pH, easily clumped by humidity; found naturally, known since at least around 1400.
Other Names: Zinc sulfate, white copperas, white vitriol, zinck, zinke, zinc vitriol, [G] zink, zinken, zinn, [Fr] zinc
Dye Use: Used with slaked lime (calcium hydroxide) to reduce oxygen in indigo dye vats. Usually mixed as a paste with the calcium and lime. Added to dyepot to strengthen a weak indigo bath. Zinc works well with synthetic indigo.
Best On: Cotton, linen, hemp, ramie, etc, as well as wool.
Dye Recipe: Use 1/3 tsp zinc, 1 tbsp slaked lime, 1 gal water to reduce residual oxygen from indigo bath.
Safety: Hazardous chemical! Toxic if ingested or inhaled. Finely-ground zinc powder is a reactive metal that can burst into flame if mishandled. Do not boil. Store away from acids and oxidizing agents.
Disposal: Dispose at Hazardous waste facility.
Alternative: Ammonia + thiox, urea
Source: Chemical supply house
CODES: c = cup; gal = gallon; lb = pound (weight); tbsp = Tablespoon; tsp = teaspoon / [AF] Anglo-French; [Ar] Arabic; [AS] Anglo-Saxon; [Dan] Danish; [Du] Dutch; [Fr] French; [Ger] German; [Gk] Greek; [It] Italian; [L] Classical Latin; [LL] Late Latin; [ME] Middle English; [ML] Modern Latin; [OE] Old English; [OF] Old French; [ON] Old Norse; [OS] Old Saxon; [Port] Portuguese; [Sp] Spanish; [Sw] Swedish / CE = Common Era; BCE = Before Common Era