Very low iron content in the raw materials.

Iron compounds make ordinary cement grey.

Materials are selected to exclude them.

Firing and grinding preserve the colour.

It is otherwise a true Portland cement.

Grey competes with any pigment added.

Colours come out dulled and chalky.

The achievable range stays in earth tones.

A white base lets pigment read truly.

Pale and saturated shades become possible.

Considerably, and it is underrated.

Grey cement varies between works and loads.

That variation shows in finished colour.

White is made to a controlled whiteness.

So a second batch matches the first.

Architectural and coloured concrete.

Precast facade panels and cast stone.

Glass-reinforced concrete and terrazzo.

Tile adhesives and grouts.

White and coloured renders and mortars.

Several times the price of grey cement.

Raw materials are selective.

The process is more demanding.

So it is specified, not used generally.

Appearance has to justify it.

Contamination, and it shows immediately.

Grey cement residue in a mixer.

Dirty or iron-bearing aggregate.

Rust from tools or reinforcement.

Any of these mark the finished surface.

Dedicated or thoroughly cleaned equipment.

Clean pale aggregate and sand.

Clean water for mixing.

Protection from site staining while curing.

These are specification, not refinements.