Enamel is made up of several minerals, mainly silica, and is found in powder form which is then mixed with a liquid before being deposited on a metal support and fired in a kiln several times.
The addition of pigments to the enamel powder allows for a wide range of colours, but will have an impact on the firing times which must be very precise.
Enamelling is a technique that can be used in a relatively simple way by producing a white dial for example.
Other, more complex dials can be created such as cloisonné dials where many squares can appear with different colours of enamel. Also, in the past, the dials of grand complications were often equipped with numerous dials for the different counters.
In order to avoid breakage due to expansion at the time of temperature change, many enamel dials were also equipped with counter enamels, i.e. a second enamel plate under the dial. This made these dials thick, but their great advantage is their almost unalterability.
These dials can sometimes have some imperfections, that’s how you can recognize a real enamel dial from a fake one, but their colour will never change. It will go through the centuries and remain the same.
This inalterability also comes from the fact that each colour is fired one after the other to harden the material.