An opacifier is a chemical component added to glazes to reduce or eliminate their transparency, creating a visually opaque and uniform surface. These materials, by scattering and refracting light in multiple directions, prevent the color and texture of the underlying clay from influencing the final appearance of the glaze.
Among the most commonly used opacifiers are tin oxide, titanium oxide and zirconium silicate. Each brings distinctive qualities in terms of whiteness, chemical stability and visual effect. Historically, opacifiers played a crucial role in the development of ceramics that mimicked the appearance of white porcelain, as well as in the generation of brightly colored and contrasting glazes in Islamic, Renaissance and contemporary ceramics.
Interesting Fact
The addition of opacifiers to the glazes allowed craftsmen and craftswomen of different periods to achieve bright, solid colors on a white or uniformly colored surface, emulating the aesthetics of Chinese porcelains without the need to achieve the high temperatures and exact composition of porcelain clay.
Helpful Tip
Before using an opacifier, perform small tests. Adjust the amount and type of opacifier to obtain the desired level of opacity without compromising the gloss or smoothness of the glaze. Keep a record of the proportions and firing conditions to easily reproduce the result.
