1. Solubility: In water, Nigrosine Black forms a bluish-purple solution, displaying good solubility, which allows it to interact with hydroxyl or amino groups in fiber materials, thereby achieving dyeing.The addition of sodium hydroxide solution results in the formation of a brownish-purple precipitate. Nigrosine Black is soluble in ethanol, exhibiting a blue color, and in concentrated sulfuric acid, it also appears blue; upon dilution, it changes to purple with a precipitate forming. Nigrosine Black is nearly insoluble in ether, acetone, benzene, chloroform, petroleum ether, and liquid paraffin.

 2. Storage: Nigrosine Black should be kept away from contact with oxidizing agents during usage. When storing, ensure that the storage container is tightly sealed and store it in a cool and dry place.

Nigrosine Black mainly used for dyeing on leather, it typically appears as a dark organic dye that imparts a deep black color to leather. Nigrosine Black also be used for dyeing of paper, wood, soap and wool. It has widespread applications in industries such as paper and printing.