Sir William Henry Perkin - Cable Street, London, UK - Blue Plaques on Waymarking.com

The blue plaque, that is in good condition, reads:
On the edge:
"Stepney Historical Trust"
In the centre:
"Sir William / Henry Perkin F.R.S. / discovered the first aniline dyestuff, / March 1856, / while working in his home laboratory / on this site and went on to / found science-based industry. / 1838 - 1907".

"Nearly everything on the planet can be described in terms of chemicals. Technological advances are fueled by them, and new discoveries are made because of them. These technological breakthroughs are often applied to the world at large, and a good example of this is the discovery of aniline dyes. Aniline dyes are considered synthetic organic compounds, a carbon-based chemical that is altered by another substance, or synthesized.

Mauvine, the first aniline dye, was discovered by 18-year-old William Henry Perkin. He was trying to create a synthetic version of the anti-malaria drug quinine on a challenge given by his professor in 1856. Perkin was trying to find a solution to the task, and oxidized the chemical aniline, a coal-tar byproduct, with the chemical potassium dichromate. This reaction caused a thick black substance to form in Perkin's flask, which is a common symptom of a failed experiment in organic chemistry. Later, when Perkin was cleaning his flask, he found that the substance dissolved in alcohol to form a purple liquid, which was later found to take to textiles extremely well, thus leading to the advent of the aniline dye industry.

Aniline dye products today come in a variety of colors, ranging from soft hues to bright primary colors. Aniline dye is used in a variety of fields, but is most commonly found in the leather and woodworking industries. Aniline wood dyes are often hailed as having an advantage over wood stains for their clarity and saturation. Aniline dye does not leave pigmentation on the surface of the wood, and is purported to leave the finished product less “muddy” in appearance. Not only does aniline dye stain leave no pigmentation behind, but it penetrates all parts of the wood equally, unlike stains which absorb more color into parts of the surface that are more porous.

Similarly, aniline dyed leather does not lose any structure or grain pattern, and is often considered to be of a higher quality than other types of dyed leather. There are several different processes in which leather can be aniline dyed, each with its own advantages and disadvantages. Aniline dyed hides may vary widely in quality. Many people are beginning to dye their own hides using commercially available dye solutions, which are readily available in most leather supply stores or craft shops.

Commercially available aniline dyes are available in the form of powders that can be dissolved in either water, alcohol or oil. Each type of aniline dye has its own safety precautions, mixing procedures and application processes, and it is recommended that users follow the manufacturer's instructions when using aniline dye for any projects. Aniline dye is considered toxic in some forms, and proper safety precautions should be observed if undertaking a project utilizing aniline dye."

Source Wise Geek website.