Rutile and anatase titanium dioxide, plus the extender whites that work alongside them. Opacity, brightness and durability are each a separate decision.
Past a certain loading, adding more pigment stops buying you more opacity.
Light scatters at the boundary between pigment and binder, and that scattering works best when particles sit roughly half a wavelength apart. Crowd them closer than that and their effects start to overlap, so each extra particle contributes less than the last. That's why a well-extended formulation can actually hide better than a heavily loaded one — and why opacity is specified as a measured contrast ratio, not a percentage in the tin.
92–98
% TiO2 content
Across the rutile range, from coated general grades to high-purity.
The formulation is designed backwards, starting from the contrast ratio needed.
The contrast ratio needed at the actual film thickness is fixed first. Everything else follows from that, including how much titanium dioxide is really needed.
The extender package is designed to space the white out efficiently, keep pigment loading below the critical point, and carry the sheen the finish needs.
The white is broken down to individual particles and kept that way. Particles re-clumping after the mill is the most common cause of opacity lost between lab and plant.
Whiteness, tone and contrast ratio are checked against the standard, with accelerated weathering data where the system is headed outdoors.
Crystal form and treatment are chosen against the exposure and the system.
Surface treated · universal
The durable, general-purpose white. High refractive index, strong hiding power, and treated to weather well and mix in easily across most systems.
Untreated · high whiteness
A cleaner, bluer white that is gentler on equipment, for interior systems, fibre and applications where controlled chalking is actually wanted.
Calcium carbonate · talc · barytes
Functional fillers that space out the titanium dioxide, carry sheen and control flow. Chosen on particle shape and oil absorption, not on whiteness.
No single number tells the whole story.
How much of the pigment is actually the scattering material. The rest is functional surface treatment, not filler.
Sets refractive index and light stability together. This is the first decision to make, and it cannot be changed later in the formulation.
Tuned for scattering visible light. Finer material scatters blue light and tints the white; coarser material simply loses hiding power.
Sets how much binder the pigment needs, and so how much can be loaded before opacity and film quality start to fall away.
The brightness and undertone the white brings to every tint made from it. A yellow-toned white cannot be fixed later without losing brightness.
Grit that survives into the film. This governs suitability for thin films, gloss finishes and fine printing more than any optical figure does.
Rutile, for anything exposed to daylight. Its refractive index is higher, so it hides better, and it holds up far longer in the sun. Anatase is chosen where a cleaner, bluer white or gentler abrasivity matters more than durability, or where controlled chalking is actually wanted.
Because scattering works best when particles sit roughly half a wavelength apart. Crowd them closer and their effects overlap, so each extra particle adds less. Push loading past a critical point and film quality falls away too.
Silica and alumina coatings shield the titanium dioxide surface from light-driven reactions that would otherwise degrade the binder. Organic treatments help the pigment wet and mix into a given system. Together they're what makes a grade weatherable, easy to disperse, or both.
Partly, and profitably — if the particle size and shape are chosen to space the white out rather than just dilute it. The right structured extender can hold hiding power steady at a lower titanium dioxide loading; a poorly chosen filler just loses opacity.
Against measured brightness and tone values on a standard test panel, not by description. Tone matters as much as brightness — a yellow-toned white shifts every colour mixed from it, and that cannot be fixed later without losing brightness.
Send us your binder system, the contrast ratio required and the exposure the film will see. We will come back with the grade, loading and extender balance.
