Editing Colourant

{{Short description|Substance used to change the colour of a material or surface}}
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 [[food colouring|foods]] and [[plastic colorant|plastics]]. Colourants work by absorbing varying amounts of [[light]] at different [[wavelength]]s (or [[frequencies]]) of its [[visible spectrum|spectrum]], transmitting (if translucent) or reflecting the remaining light in straight lines or [[Light scattering|scattered]].

Most colourants can be classified as [[dye]]s or [[pigment]]s, 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 [[Binder (material)|binders]] and [[Filler (materials)|fillers]] are added, for example in [[paint]]s and [[ink]]s. In addition, some colourants impart colour through reactions with other substances.

Colourants, or their constituent [[chemical compound|compounds]], may be classified chemically as [[inorganic]] (often from a mineral source) and [[organic compound|organic]] (often from a [[biological pigment|biological]] source).

== Regulation ==

=== United States ===

In the US, the [[Food and Drug Administration]] (FDA) regulates colourants for food safety and accurate labelling.<ref>{{cite web|url=https://www.fda.gov/food/ingredientspackaginglabeling/foodadditivesingredients/ucm094211.htm#coloradd|archive-url=https://web.archive.org/web/20130321053944/http://www.fda.gov/Food/IngredientsPackagingLabeling/FoodAdditivesIngredients/ucm094211.htm#coloradd|url-status=dead|archive-date=March 21, 2013|title=Overview of Food Ingredients, Additives & Colors|publisher=[[Food and Drug Administration]]}}</ref>

== See also ==
* [[Food colouring]]

== References ==
{{Reflist}}

{{Authority control}}

[[Category:Color]]


{{Colour-stub}}

[[ja:色素]]
[[pt:Corante]]