What is pigment? Types, production and uses

Pigment is a fine-grained solid material that does not dissolve in the medium it is applied to, providing colour and opacity by selectively absorbing and scattering light. The "visible" part of paint is the pigment; the resin binds it to the surface, while the solvent brings it to an applicable consistency.

What is pigment?

The fundamental difference between pigment and dye is solubility: dye dissolves in the medium and disperses at the molecular level, while pigment remains suspended as particles. This difference generally makes pigment's light and weather resistance higher; however, pigment performance depends not only on its chemistry but also on particle size and distribution.

The main criteria for evaluating a pigment are: opacity (hiding power), tinting strength, lightfastness, weather resistance, chemical resistance, oil absorption value and dispersibility.

How is it produced?

The production method varies depending on the pigment class.

• Titanium dioxide (TiO₂): there are two main processes. The sulphate process dissolves ilmenite ore in sulphuric acid; the chloride process reacts the ore with chlorine, distilling the intermediate TiCl₄ product and then burning it. The chloride process yields a brighter and more durable rutile product with a lower waste load.
• Iron oxide pigments: produced either by grinding natural ore or through controlled precipitation and calcination of iron salts (synthetic). Synthetic ones have markedly higher colour consistency.
• Organic pigments: produced through multi-step organic reactions such as azo coupling and phthalocyanine synthesis; particle size and crystal form are then adjusted through a "pigmentation" step.
• Carbon black: obtained through the controlled incomplete combustion of hydrocarbons.

In every case, the final step is the same: surface treatment. Particles are coated with alumina, silica or organic agents; this coating both improves dispersibility and, in pigments with photocatalytic activity such as TiO₂, prevents degradation of the binder.

Types and varieties

Which sectors use it?

• Paints and coatings: decorative, industrial, automotive and powder coatings — the largest market for pigments.
• Plastics: provides colour and UV protection to polymers via masterbatch; resistance to processing temperature is essential.
• Printing ink: tinting strength and particle fineness are decisive in packaging and publication printing.
• Cosmetics: used in make-up and sunscreen products; purity and regulatory compliance are paramount here.
• Packaging and paper: coated paper finishing and brightening.
• Construction: coloured concrete, roof tiles, grout — iron oxides dominate in this area.

Turkish market and production

Türkiye's pigment sector is largely import-dependent; almost all titanium dioxide and organic pigments are sourced from abroad. In contrast, the country has a rich reserve base of filler minerals (calcium carbonate, talc, barite) and is a producer and exporter in this group.

The sector's agenda is progressing on three fronts: TiO₂ cost and supply security (formulators are looking for fillers and rheology solutions that maintain hiding power while reducing the TiO₂ ratio), regulation (classification changes for certain pigments and fillers, restrictions on cosmetic and food contact applications) and sustainability (heavy-metal-free alternatives, low-energy production). Current developments are listed in the news section below.

Technical properties

Colour is only the first item on the list when selecting a pigment. Formulators evaluate the following parameters together.

Tinting strength and hiding power depend more on how well the pigment is dispersed than on its chemistry. The same pigment provides significantly higher colour yield when well dispersed compared to when poorly dispersed; therefore dispersion quality is a direct part of the cost calculation.

Points to consider in selection and sourcing

• Evaluate the colour sample in your own system. A pigment's appearance in the supplier's colour card will not be identical in your binder.
• Calculate tinting strength as cost/effect, not by weight. A pigment with a low price per kilogram can end up costing more overall if it requires a higher dosage to achieve the target colour.
• Request batch-to-batch colour tolerance in writing. The acceptable ΔE value for serial production should be defined in advance.
• Specify the application temperature. Some organic pigments degrade at processing temperature in plastics processing.
• Clarify the regulatory scope. Separate compliance certificates are required for food contact, toy and cosmetic applications.

Frequently asked questions

What is the difference between pigment and dye?

Pigment does not dissolve in the medium it is applied to and disperses as particles; dye dissolves. This is why pigment generally has higher light and weather resistance, though mechanical dispersion (grinding) is required for a good result. Dyes are preferred in areas requiring transparency, such as textiles and inks.

What is the difference between rutile and anatase titanium dioxide?

Both are crystal forms of TiO₂. Rutile has a higher refractive index; its hiding power and outdoor weather resistance are better, which is why it is standard in paint. Anatase is more photocatalytic; since it can degrade the binder in outdoor use, it is mainly used in indoor applications, paper and photocatalytic surface applications.

Why is pigment dispersion a separate area of expertise?

Pigment particles agglomerate during production. To achieve the full tinting strength and hiding power, these agglomerates must be broken down in mills and then prevented from re-forming with the help of a dispersant. Poor dispersion manifests as colour shift, settling, gloss reduction and flocculation.

Are fillers (extenders) considered pigments?

Technically, fillers are also insoluble particulate solids, but since their refractive index is close to that of the binder, they do not provide hiding power on their own. Their role is to add bulk, adjust rheology, improve mechanical properties and reduce cost.

Why do effect pigments change colour depending on viewing angle?

Metallic and pearlescent pigments do not only absorb light; they reflect it directionally from the surfaces of flake-shaped particles and create thin-film interference. The colour observed therefore depends on the viewing angle; the sense of depth in automotive paint comes from this mechanism.