A dispersion is a mixture in which fine solid particles are distributed throughout a liquid without dissolving in it. Paints, printing inks, many coatings and numerous industrial products are dispersions - pigment particles suspended in a liquid carrier.
Making one involves more than stirring solid into liquid. The particles must first be wetted, so the liquid displaces air from their surfaces; then broken down, since raw powders arrive as clumps rather than individual particles; then stabilised, so they stay separated instead of re-aggregating and settling. Each stage needs different treatment, and skipping the wetting stage tends to produce a product that looks acceptable and fails later.
Particle size drives most of the properties that matter. In a pigment dispersion it determines colour strength, gloss and opacity - the same pigment dispersed well and dispersed badly gives noticeably different results. This is why milling and dispersion equipment matter and why the process is specified rather than left to judgement.
The distinction from an emulsion is simply that a dispersion suspends solids while an emulsion suspends liquid droplets. Both rely on stabilisers and both can separate on standing. See dispersion manufacture and pigments.
Ask how particle size will be measured and controlled, and get it into the specification. In pigmented products it is the parameter that determines colour strength and gloss, so leaving it unspecified invites variation that customers will notice. It is also worth agreeing how a dispersion will be assessed on delivery, since settling during transport is normal for some products and a specification that ignores it will generate avoidable rejections.
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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 Tell us if something here is out of date.
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