Black and white developer Photographic grade Hydroquinone 123-31-9
White needle-like crystals. Combustible. Melting point 172-175°C. The boiling point is 285-287°C, the relative density is 1.328 (15°C), the flash point is 165°C, and the self-ignition point is 516°C. benzene. It is easy to form when it is exposed to light in the air, and oxidizes in solution.