dye-fixer
nounUK /ˈdaɪ ˌfɪksə/
US /ˈdaɪ ˌfɪksər/
A dye-fixer is a special liquid that helps color stay on cloth and not wash out.
Mom added dye-fixer to the washing machine so my red shirt would not fade.
OTHER MEANINGS
2. A chemical used in photography to make developed images permanent.
The photographer soaked the print in a dye-fixer before hanging it to dry.
3. A substance added to ink to keep it from smudging on paper.
The printer ink contains a dye-fixer that helps it dry quickly.
4. A person whose job is to treat newly dyed materials so the color lasts.
The dye-fixer at the factory checked each batch of wool.