Dye - What is a dye?
A type of colourant; dyes alter the colour of other materials because they selectively absorb different wavelengths of light. The colour a dye produces is determined by the particular wavelength(s) of light that are transmitted or reflected by the dye, and not those that are absorbed.
Dyes are usually distinguished from pigments in two ways; dyes have an affinity for the substrate to which they are applied (there is an attraction between the two) and they are soluble (they will dissolve in a solvent to form a solution). Most dyes are liquid dyes that have been dissolved in water (or another solvent), although some are made in a paste form. They are either naturally occurring or synthetic organic chemicals; the earliest dyes were made from animals, minerals, and, most predominantly, plants. The first synthetic dyes were produced in the 18th and 19th centuries and quickly replaced natural dyes because they were less expensive, offered a vastly superior range of colours, and could be used to add a variety of important properties to materials (besides a specific colour) such as transparency, purity, and strength of colour.
In labelling, dyes are used to colour the face material used to produce coloured labels and as the colourant in some printing inks, where they are absorbed by the fibres in paper face materials and impart a number of important properties including transparency, and purity and strength of colour.Go Back to Glossary