OXYDE D'ETAIN

Tin oxide, in powder form, is the main agent giving deep white glazes.

Add 2-10% (by dry weight in relation to the glaze) to a transparent glaze,

The glaze after firing will take on an opaque white colour.

The resulting white glaze can be coloured with metal oxides or colouring oxides (often referred to as mass colours)

Tin oxide is certainly the first opacifier used in glazes.

The degree of opacification depends on the nature of the glaze: glazes containing high levels of alkali and barium inhibit the effect of tin oxide, while zinc and calcium oxides favour opacification.

TIN OXIDE

This is the most effective opacifier used in ceramics; it used to be commonly used, but nowadays its high price has considerably reduced its use, being replaced by other opacifiers.

It produces bluish-white glazes that are opaque at both high and low temperatures.

In addition, between 4 and 7% it produces semi-opaque glazes and between 8 and 10% very opaque ones.

It is also used in the manufacture of stains.