A colourant/colour additive (British spelling) or colorant/color additive (American spelling) is a substance that is added or applied in order to change the
colour of a material or surface. Colourants can be used for many purposes including
printing,
painting, and for colouring many types of materials such as
foods and
plastics
Plastics are a wide range of synthetic polymers, synthetic or semi-synthetic materials that use polymers as a main ingredient. Their Plasticity (physics), plasticity makes it possible for plastics to be Injection moulding, moulded, Extrusion, e ...
. Colourants work by absorbing varying amounts of
light at different
wavelengths (or
frequencies
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...
) of its
spectrum, transmitting (if translucent) or reflecting the remaining light in straight lines or
scattered
Scattered may refer to:
Music
* ''Scattered'' (album), a 2010 album by The Handsome Family
* "Scattered" (The Kinks song), 1993
* "Scattered", a song by Ace Young
* "Scattered", a song by Lauren Jauregui
* "Scattered", a song by Green Day from ' ...
.
Most colourants can be classified as
dye
A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution an ...
s or
pigments, or containing some combination of these. Typical dyes are formulated as solutions, while pigments are made up of solid particles suspended and are generally suspended in a vehicle (e.g., linseed oil). The colour a colourant imparts to a substance is mediated by other ingredients it is mixed with such as
binders and
fillers are added, for example in
paint
Paint is any pigmented liquid, liquefiable, or solid mastic composition that, after application to a substrate in a thin layer, converts to a solid film. It is most commonly used to protect, color, or provide texture. Paint can be made in many ...
s and
inks. In addition, some colourants impart colour through reactions with other substances.
Colourants, or their constituent
compounds, may be classified chemically as
inorganic (often from a mineral source) and
organic
Organic may refer to:
* Organic, of or relating to an organism, a living entity
* Organic, of or relating to an anatomical organ
Chemistry
* Organic matter, matter that has come from a once-living organism, is capable of decay or is the product ...
(often from a
biological
Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary in ...
source).
Regulation
United States
In the US, the
Food and Drug Administration (FDA) regulates colourants for food safety and accurate labelling.
See also
*
Food colouring
References
Color
{{Colour-stub
ja:色素
pt:Corante