Ancient fragments of fabric colored with red dye were found in a desert cave ... They can produce a red color due to the presence of carminic acid or kermesic acid molecules in their bodies.

“An acid or an alkali will give you more colours from one dye pot. You can dilute some lemon juice in water, pop a swatch of the dyed fabric in and see what happens. In another jar, use ...

It is not unfrequently desirable to know, with regard to dyed stuff, in what manner it has been dyed, and what dyeing material has ... By chlorine and nitric acid, on the contrary, they are ...