CERAMIC DECORATION—FRANCHET. 647 
admit that, while they suit certain circumstances, they are deplorable 
in many others. A mat finish can be obtained with great facility 
with all shades without exception, but there are three which have 
been adjudged worthy of serious consideration. These are the brown 
mat finish obtained with rutile; the green obtained by combining 
rutile with cobalt oxide; the gray blue obtained in the same way as 
the green, but by the use of a less proportion of cobalt.¢ 
The introduction of mat finishes in ceramic decoration filled a long- 
felt want. They are necessary because they make possible the use 
of certain motifs of sculpture that lose much of their character with 
brilliant glazes. The best things should not be abused, however. The 
mistake has been made of applying mat finishes to everything, 
notably in architecture. The Sévres manufactory has set the 
example, as, indeed, it may well do, since it is our great national 
establishment for ceramic study. That factory was responsible for 
the construction of the immense portico of stoneware with a mat 
finish seen to-day in the square of Saint-Germain-des-Pres in Paris. 
This sample of modern ceramic architecture bears witness to our 
inferiority to the Orient, where they use brilliant enamels ex- 
clusively with a skill that might well inspire our architects and 
ceramists. Paris to-day numbers several edifices of mat stoneware. 
Let us hope that they will not be multiplied. 
The tones communicated to glazes and covering layers by metallic 
oxides are, from the standpoint of coloration, closely dependent 
on the nature of the atmosphere of the kiln. The flames that come 
from the hearth of a kiln and penetrate into the firing chamber, 
inclosing the articles to be fired, are possessed of different properties 
according to their composition. They may be oxidizing, neutral, or 
reducing. <A flame is oxidizing when it is saturated with oxygen 
derived from the air and contains not only an excess of carbon but 
an excess of oxygen. Under these conditions it is blue in color. A 
flame is neutral when it contains neither carbon nor oxygen in excess. 
It still has a blue tint, but this is less intense than in the preceding 
case. A flame is reducing when there is a lack of oxygen in it and 
it is saturated with carbon. It is then yellow in color. It is there- 
fore easy to understand that these flames, having different composi- 
tions, will exert considerable influence on the colors which may be 
submitted to their action. The ceramic ware which we usually see is 
fired with an oxidizing flame. 
Two kinds of decoration may be obtained with a reducing fire; 
one at a low temperature, the other at a high temperature. The 
decoration with a low temperature is represented by the faiences 
“All the formule for mat finishes have been published many times, and are 
known to-day to all ceramists. 
45745°—sm 1909——42 
