What is the 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

Glossary

Pigment - What is a pigment?

Definition of PIGMENT:

A type of colourant; pigments alter the colour of other materials because they selectively absorb different wavelengths of light. The colour a pigment produces is determined by the particular wavelength(s) of light that are transmitted or reflected by the pigment, and not those that are absorbed.

Pigments are usually distinguished from dyes in two ways; pigments do not have an affinity for the substrate to which they are applied (there is no attraction between the two) and they are insoluble (they do not dissolve in a solvent, instead they are suspended in the solvent). They are a dry colourant that is ground into a fine powder made up of small particles; this powder is then suspended in a vehicle or added to a binder, which allows the pigment to be transported as required and provides adhesion so the pigment can adhere to a substrate.

Pigments can be natural (including earth and mineral pigments and biological pigments taken from animals and plants) or synthetic; pigments were made synthetically as early as 2BC but were only developed industrially in the 18th and 19th centuries. Most pigments are organic, as these tend to produce brighter and stronger colours than inorganic pigments.

In labelling, pigments are used to make coatings for face materials that are to be used to make labels (where they determine a variety of characteristics such as colour, brightness, whiteness, opacity, surface smoothness, and printability) and as the colourant in some printing inks, where they sit on top of the face material and impart a number of important properties including transparency or opacity, and resistance to heat, light, chemicals, water, and oils.

Three different colours of pigment are sat in glass dishes next to a colour chart.

Here is the Harvard-style citation to use if you would like to reference this definition of the word pigment:
Label Planet (2020) What is a pigment? | Pigment Definition. Available at: https://www.labelplanet.co.uk/glossary/pigment/ (Accessed: January 1, 2024).

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