48 
KERAMIC STUDIO 
varying from one to ten per cent., yields a wide range of tints, 
from bright brick red to a pale pinky salmon. These pig- 
ments may be mixed together and a gi'eat variety of tints 
obtained. 
Only pink is needed for a complete color scheme. But 
while the other colors have a certain suavity which makes 
it difficult to combine them discordantly, the pink is not easy 
to introduce in any harmonious scheme. The base is a mixture 
of bichromate of potash, alumina, and tin, calcined at a high 
heat. The process is risky and troublesome, and as practically 
the same result can be had from ordinary crimson glaze stains, or 
strong underglaze pink, which may be bought from any ceramic 
color dealer, it is useless to take the trouble to make it. The 
stone and spar in the body have a property of destroying the 
pink tone, but this can be obviated by the introduction of a 
little carbonate of baryte. A good general formula is 
Pink Stain 3 parts 
Carbonate of Baryte 1 part 
Ground together. 
1 part of above to 8 White Paste. 
Although other oxides are used, this gives sufficient range for 
any ordinary purposes, and it is only necessary to indicate for 
the guidance of those who are not in the vicinity of a pottery 
how they can prepare their pieces themselves. It is best per- 
haps, at the outset, to begin with a plaque or slab. This can 
easily be done, if the operator is careful. A flat pancake like 
disc of modelling clay is beaten out flat on a bench, and the 
surface trued and polished. It is then cut with a knife to the 
required size and shape. If rectangular, the knife may be 
passed along a straight edge or template. The sharp edges 
should be lightly softened with a sponge or horn. Then a 
wall or dyke of clay should be built round the clay slab, 
about two and one-half or three inches high, and about 
the same distance from the edges of the slab. A sufficient 
quantity of plaster-of-paris should be mixed with water and 
poured over the clay slab, filling the "dyke" to the edges. 
When it has "set," the clay wall may be removed, and the 
clay slab taken away from the plaster, leaving a mould. This 
should dry a couple of days in a warm place (not too warm), 
and the mould is then ready to make the pate-sur-pate slab, 
which may be made either of solid colored paste, or of white 
paste with a colored coat or film. The latter is the more 
economical, and quite as satisfactory in its results. Say a 
dark blue ground is wanted. The blue slip is applied to the 
inside of the mould with a large brush, to the thickness of about 
one-eighth inch. So long as the coat is nowhere thinner, a 
little unevenness in the coat does not matter, as the surface, 
which is where it touches the mould, must be level. Then the 
mould is filled with white slip level with the surface. As 
absorption proceeds, the slip will sink, and more slip must be 
poured in until the sinking has ceased and the paste is flush 
with the top of the mould. In about half an hour it will have 
hardened to the consistency of ordinary clay, and it may then 
be scraped perfectly level with a straight edge or a modeller's 
scraper. It should then be left over night and the next morning 
it will be found to have contracted away from the sides of the 
mould all round. A board or plaster "bat" should then be 
placed upon it, the board and the mould turned upside down, 
and the slab will be finished. It should be dried perfectly and 
passed through an easy kiln, when it can be handled without 
risk, and is ready to work upon. 
If the slab is made of solid stained paste, the process is, 
of course, the same, excepting that the painting of the mould 
is not necessary, although, in any case, it is advisable, as it 
prevents blistering. 
If a vase is needed, the same process is gone through, ex- 
cept that when the mould is filled, it is only kept full of slip 
until the absorption has caused a sufficient thickness of slip 
to adhere to the sides of the mould. Then the slip should be 
poured out. Care too should be taken in the case of a coated 
vase to paint over the seams very thickly after the two sides 
of the mould are joined together. 
MISS MASON'S PITTSBURG CLASS— ELIZABETH SCROGGS 
(Treatment page 66) 
