Enamels and enamelling; an introduction to the preparation and ...

colour ;
VI.
PIGMENTS.
Enamel masses have the property of acquiring any desired
and, when properly prepared, the colours are character-
ised by brilliancy, lustre and indestructibility qualities which
explain the preference shown for coloured enamels in the production
of very valuable works of art.
Although, in the case of enamels for technical purposes,
-colour is a minor consideration in comparison with the inner
qualities of the product, viz., power of withstanding
the action
of chemicals and considerable fluctuations of temperature,
beauty of colour is nevertheless a matter of some importance
even in such enamels. Thus it is well known that cooking
utensils, for example, that are coated with nicely coloured
enamels, have a better sale than those covered with white
enamel, notwithstanding
able than the others.
that the latter is much more service-
The pigments employed in this industry are all of the
metallic-oxide group. As already mentioned, certain oxides
of the heavy metals have the property of colouring glass ;
and
though very highly coloured glasses are used to colour certain
enamels, it must be remembered that the pigmentary principle
of these glasses is an oxide, and consequently one is justified
in saying that the colour of all enamel masses is due to certain
metallic oxides.
The object of the present work is twofold,
in that it is in-
tended to treat of the preparation of enamel masses both for
artistic and industrial purposes. The technical man, who is