Colour fan

Decorative colours for porcelain finishing

The colour palette for porcelain finishing depends on the subsequent decorative firing. The only exception to this is the underglaze, which can only be produced using metal oxides due to the high firing temperature. In modern inglaze decoration, the colour palette is much wider, as can be seen in the picture as an example. But even with inglaze colours, the colour base is usually a metal oxide that has been refined with mineral or other chemical compounds. The colours all have one thing in common: they have to withstand a temperature range between 1,100 °C and 1,400 °C in decorative firing. This is exactly what makes it so difficult.

Due to the lower decoration firing temperature, many more colours are available for onglaze decoration, e.g. metal oxides with glass fluxes, precious metal preparations (gold, silver, platinum) and synthetic colours such as ferro-samba colours.

Much more important than knowledge of the composition of porcelain colours is knowledge of the colour deviations in porcelain production. The play of colours on porcelain reacts very differently to printing on paper! As a general rule, we recommend sticking to the standard colours available from a factory. Architects, designers and advertising agencies in particular like to make things difficult for porcelain manufacturers with their special colour and design requirements (corporate design). In the case of prescribed colour requests, the industry can only approximate the colour specifications, but can never match them exactly!

It is definitely not possible to implement HKS or RAL colours exactly, especially spectral colours or gradients! It can also happen that one and the same vignette from one and the same manufacturer appears differently on different porcelain items, or that the colour gloss is perceived differently. This is due to the fact that the masses from which the hollow and flat parts are made are of different consistencies (solid/liquid). Although the white-glazed porcelain looks the same to the eye, it reacts differently in the finishing process.

Of course, we always endeavour to meet the colour specifications of our customers when producing vignettes or customer-specific decorations. However, these endeavours often come up against natural limits. Vignette or decorative colours are created by adding pigments in the classic mixing process. Just as the master painter mixes a colour composition, this is also done in the porcelain factory. A 100% match with a specification (RAL/Pantone) is never achieved in porcelain production. There are always only approximate values!

Such production-related colour deviations are the same for all porcelain manufacturers and cannot be avoided. It is true that the more precise and modern the colour pigments are added, the lower the risk of colour deviation.