p-Methylaminophenol sulfate

p-Methylaminophenol sulfate (CAS 55-55-0), commercially known as Metol, is a photographic developing agent and reducing compound used across imaging and specialty chemical applications.

It functions as a primary electron donor in developer formulations, enabling controlled silver halide reduction in photographic and radiographic processing. In photographic and X-ray film processing, Metol is a core component of developer baths.

It is typically combined with hydroquinone to produce fine-grain, high-acutance image development. Printing plate and graphic arts workflows use Metol-based developers where precise tonal gradation and developer activity control are critical.

In hair dye formulations, it acts as a coupler or oxidation base, contributing to color development in permanent colorant systems. Specialty industrial imaging processes, including document archiving, also rely on Metol.

Micrographic film development utilizes this compound for its consistent reducing performance across a range of pH and temperature conditions. The material is supplied as a white to off-white crystalline powder for industrial use.

Technical and photographic grades are the most commonly traded forms, with purity specifications typically ranging from 98% to 99%+. Packaging is available in kilogram-scale bags through to bulk quantities.

These bulk quantities are suited for industrial developer concentrate manufacturing. The compound remains a standard in the chemical industry for high-precision imaging and specialized oxidation reactions.