Pigments

Pigments are insoluble colourants, dispersed rather than dissolved in the liquid or solid carrier they colour - unlike dyes, which dissolve fully into the medium. Pigments are classified through the Colour Index International, a reference system jointly managed by the Society of Dyers and Colourists in the UK.

How Pigments Are Used in Manufacturing

Pigments are combined into a liquid carrier through dispersion manufacture, typically using milling equipment to achieve the target particle size and colour strength - central to coatings and paints manufacture.

Regulatory Considerations

Pigment compliance in the UK is assessed against REACH and CLP frameworks, with heavy metal content, thermal stability and dispersion quality typically covered in a supplier's declaration, safety data sheet, technical data sheet and certificate of analysis.

Why Dispersion Matters More Than the Pigment

A pigment's performance in a finished product depends heavily on how well it has been dispersed. The same pigment at the same loading can give noticeably different colour strength, gloss and opacity depending on whether the particles have been properly wetted and broken down into individual particles rather than left as agglomerates.

This has a direct commercial consequence: better dispersion means more colour from less pigment, and pigment is usually among the more expensive components. It is also why colour matching between manufacturers can be difficult even with identical formulations - if the dispersion process or milling equipment differs, the colour can differ. See dispersion.

Organic and Inorganic

Pigments divide broadly into inorganic and organic types with fairly consistent trade-offs. Inorganic pigments tend to offer excellent durability, opacity and heat resistance with more muted colours, at lower cost. Organic pigments offer brighter, cleaner and more intense colours, generally at higher cost and sometimes with lower lightfastness.

Selection therefore depends on the application as much as the shade wanted. An exterior product needs lightfastness an interior one may not, and a product processed at high temperature needs heat stability. Where colour consistency between batches is critical, it is worth agreeing how colour will be assessed - visually against a standard, or instrumentally to a tolerance - as part of the specification.

Agreeing Colour Tolerance

Colour is one of the few specification parameters customers assess by eye, which makes it disproportionately visible when it drifts. Agree how colour will be judged - against a physical retained standard, or instrumentally to a stated tolerance - and who holds the reference standard. Leaving it as a matter of judgement produces disagreements that are difficult to resolve because neither party is straightforwardly wrong.

Questions to Ask a Manufacturer

• What pigment dispersion and milling capability do you have?
• Can you match an existing Colour Index reference or a specific target shade?
• What documentation do you provide confirming REACH/CLP compliance and heavy metal limits?
• Do you work with both organic and inorganic pigment systems?

Related Pages

• Coatings and paints
• Dispersion manufacture
• Dyes

Frequently Asked Questions

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Last reviewed: August 2026. Regulation and guidance change — verify anything you rely on against the primary source. Tell us if something here is out of date.