Pigment Basics: What Every Colourant Needs to Know

Colour additives — colorants — come in two families: pigments and dyes.

• Dyes dissolve completely in whatever they're applied to.
• Pigments do not dissolve. Instead, they're dispersed through the medium (a resin, ink vehicle, or plastic) while each particle keeps its own crystal or particle structure.

That one difference — dissolving vs. dispersing — is why a dye colours a solution evenly and transparently, while a pigment sits as tiny solid particles that scatter and reflect light, giving paints, inks, and plastics their opacity and depth of colour.

Humans have been colouring their surroundings since prehistory — the earliest evidence of pigment use survives in cave paintings and early cloth dyeing. Long before synthetic chemistry existed, pigments were pulled straight from nature:

Animal origin

• *Sepia* — from the ink sac of the cuttlefish
• *Prussian Blue* — made by boiling animal blood with alum and vitriol

Vegetable origin

• *Saffron lake* — a yellow dye extracted from flowers
• *Vegetable black soot* — from burning vegetable matter

Mineral origin

• Natural iron oxides (yellow and red earths)

These natural sources shared the same drawbacks: they were tinctorially weak (low colouring power), dirty in hue, fugitive (they faded quickly), and intrinsically hard in texture. Solving those problems is exactly what pushed pigment-making toward synthetic manufacture and refining — giving us pigments with far better strength, uniformity, cleaner tones, and softer textures.

Two more terms come up constantly when judging a pigment's colour:

• Full shade (mass tone): the pigment dispersed in the medium on its own, at full strength.
• Tint: the pigment mixed with a white pigment and dispersed in the medium — showing how it behaves when lightened.

And when you look closely at a drawdown, a pigment can show two different undertones depending on how you view it:

• Reflected undertone — the colour you see in light reflecting off the surface of a thick (mass tone) layer.
• Transmitted undertone — the colour you see when light passes *through* a thin layer, revealing the pigment's true underlying hue.

Sudarshan is India's leading pigment producer and a supplier to the Plastics, Paints & Inks markets globally — with over 60 years of manufacturing experience and sales in more than 60 countries.

Its chemistries span the full spectrum used across the industry — Lead chromates, Azos, Naphthols, Isoindolinones, Benzimidazolones, DPP, Quinacridones, Azo condensations, Phthalos, Cadmium and Iron oxides — brought to market under a family of brands:

• Sudaperm™ — a premium range of the highest-performance pigments, with technical benefits for the most demanding plastic and coatings applications.
• Sudafast™ — a consistently high-quality range of medium-performance organic pigments, with a growing range of colouration options.
• Sudacolor™ — a well-designed organic pigment range balancing quality, value, and ease of use.
• Sudadur™ — an extensive range of traditional inorganic pigments, delivering excellent colour, durability and coverage for demanding applications.
• Sudatex™ — a carefully selected range of concentrated water-based dispersions, ideal for textile colouration.
• Sudafine™ — a complementary range of high-pigment-content, water-based, resin-free pastes in easy-to-use stir-in form, for decorative paints and other applications.
• Sumica® — an effect pigment with a unique lustre, enhancing the aesthetic appeal of plastics, coatings and inks.