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RERAMIC STUDIO 
GRAND FEU CERAMICS 
XIV— GRAND FEU COLORS— Mat and Crystalline Glazes 
Taxile Doat 
N addition to this rich palette which 
develops on gres only in an oxidising 
fire, it was natural to determine 
another palette which would do 
well in a reducing fire, as gres 
naturally likes a reducing atmos- 
phere and receives from it its super- 
ior qualities of a fine blueish grey 
tone and a great densitJ^ Besides, 
as gres is destined to be combined 
with other materials in architectural construction, it was neces- 
sary to give to its surface a mat tone which would harmonize 
better with the character of stone and brick. 
^^'ith this end in view, the following glazes have been pre 
]3ared h\ simple mixture and grinding: 
Mat colorless glaze, slightly opaque: 
Feldspar in flour. 
30,0 
Dry pure clayey kaolin. 
40,0 
NemoLirs sand. 
28,5 
Chalk, 
20,0 
Mat ivory yellow: 
Feldspar, 
35.7 
Dry pure clayey kaolin, 
13.7 
Nemours quartzj' sand. 
43,6 
Chalk, 
15.9 
Ground natural rutile*. 
9,6 
Mat yellow: 
Feldsj^ar, 
53,0 
Clayey kaolin. 
14,0 
Quartzy sand. 
14,1 
Chalk, - 
25,5 
Rutile, 
9,6 
Red oxide of iron. 
2,4 
Mat reddish yellow: 
Feldspar, 
53,0 
ClsLyey kaolin. 
14,0 
Quartzy sand. 
14,1 
Chalk, 
25,5 
Rutile, 
9,6 
Red oxide of iron. 
4,8 
Mat violet speckled with yellow: 
Feldspar, 
33,60 
Pure cla3"e\' kaolin, 
12,89 
Quartzy sand. 
47,00 
Chalk, ^ 
15,00 
Rutile, 
6,00 
Red oxide of iron. 
6,00 
Mat crystalline yellow brown: 
Feldspar, 
33,60 
Pure clayey kaolin. 
12.89 
Quartzy sand. 
47,00 
Chalk, 
15,00 
Rutile, 
9,60 
Red oxide of iron. 
9,60 
Mat crystalline dark green: 
Feldspar, 
30,85 
Clayey kaolin. 
25,35 
Quartzj^ sand. 
36,00 
Chalk, 
28,00 
Rutile, 
18,00 
Cobalt oxide. 
12,00 
* Rutile is one of the three forms of titanium dioxide. 
Mat blueish grey green: 
Feldspar, 53,0 
Clayey kaolin, 14,1 
Quartzj' sand, 14,0 
Chalk, 25,5 
Rutile, 12,0 
Cobalt oxide, 1,2 
It is with these mat glazes that the great architectural 
fragment exhibited by vSevres at the Exposition in 1900 was 
executed. It is also with these mat glazes that I decorate 
most of my ceramics. They make a pleasing contrast with 
the bright glazes used on part of a vase, and resemlale more 
closely the mat effects of nature. 
CRYST.A.LLINE GLAZES 
After these, I must mention the crystalline glazes which 
have been received with such favor by collectors and the public 
at large. As a result of the researches made at Sevres, these 
glazes can be obtained easily, even on large pieces, on gres as 
well as porcelain. As is the case for reds, the substances 
which form their composition must first be fused. 
In order to vary the relative proportions of zinc oxide and 
potash, which are the fundamental components of crystalline 
glazes, and to establish the proportions most suitable to the 
formation of fine crystals, the two following mixtures are 
prepared : 
Frit No. I Frit No. 2 
Dry carbonate of potash, 138 69 
Zinc oxide, 162 202,5 
Quartzy sand (silica), 360 350 
These are fused in an oxidising fire, then various mixtures 
of No. I and No. 2 can be tried. 
The mixture which gives me the best results is: 
Frit No. I 85 
Frit No. 2 15 
It is necessarj^ especially for porcelain, to apply this glaze 
on biscuit fired pieces, to avoid warping and cracks which 
would occur, if the glaze was applied on raw or baked ware. 
The coat of glaze must be quite thick, so that an excess of glaze 
will flow during firing, and the piece should be placed on a high 
column made of lute or scraps of porcelain paste. 
The presence of zinc oxide in this glaze makes it necessary 
to have a strictly oxidising atmosphere, and the temperature 
at which it will develop, is that of new porcelain, 1270° C, or 
Seger cone 9. A slow cooling favors the development of 
crj^stals. 
I also use a yellow crystalline glaze which gives me very 
fine results. It is made by a fritting of the same eleilients 
with the addition of rutile: 
Frit No. 3 
Dry carbonate of potash, 138 
Zinc oxide, . 162 
Quartzjr sand, 30J 
Rutile 82 
In this case I mix the glaze as follows: 
Frit No. 2 15 
Frit No. 3 85 
If in Frit No. 3, rutile is replaced by pure titanium o.xide, 
one obtains a colorless crystalline glaze, somewhat different 
from the first as to the appearance of crystals, and which is of 
great beaut^^ 
These crystalline glazes, besides the artistic use which can 
be made of them for the decoration of small cabinet pieces, 
may be advantageously used in the decoration of tiles for 
architectural purposes, and give the latter a richness which has 
never been equalled by any other con.struction material. 
I am satisfied that ceramists who will carefullj- prepare all 
