Sulphur black can be classified as BR (Bluish-Reddish) and B(Bluish)by their different tones, and the tone and quality can be adjusted according to the customer's requirements.
Appearance: Flashing black flakes or granules
Product character: Sulphur black is insoluble in water or ethanol, it appears as green-black in the solution of sodium sulfide, appears bluish when put caustic soda in the solution of sulphur black, and appears greenish precipitate with hydrochloric acid
It's miniature soluble in cold sulfuric acid, turns to greenish blue precipitate after it's warmer, then turns to black-blue when keeps heating. Sulphur dyes have good dye-uptake and level dyeing.