2 PHOTOGRAPHIC FACTS AND FORMULAS 
both corners. Then deal with the other corners in the same 
way. Then tack the center of the top and bottom edges, then 
the sides, pulling the material taut before putting in each nail. 
The result should be without any wrinkles. It must then be 
sized. For this rub one part of starch into a cream with 
three parts of water, and boil until a clear solution is formed. 
Apply this with a stiff brush to the material, and stand the 
frame on end to dry. To make the paint, use: 
Whiting 24 parts 
Powdered glue 8 parts 
Treacle (molasses ) 12 parts 
Water 160 parts 
Soak the glue in the water for some time, add the treacle and 
melt with heat, and stir in the whiting until a smooth cream is 
obtained. Divide into three parts. For colours, obtain the 
following dry water colour pigments: ivory black 2 parts, 
ultramarine 1 part, red ochre 1 part. Mix the three pigments 
together and divide into six equal parts; to one third of the 
glue solution add one part of the pigment, to another third 
of the glue add 2 parts of the pigment, and the remainder of 
the powder to the rest of the glue: this will give three dis- 
tempers of different shades. Commercial distemper powders, 
such as kalsomine, may be used. 
Alternatively, dry canvas may be tightly stretched on a 
wooden frame, then well wetted, a mixture of dextrine and 
colour sifted over the surface from a fine sieve, and the 
surface then worked over with a stiff brush. The colours 
used may be as above or any powder colour used for house 
decoration. The colours dry much lighter. For grey and 
black backgrounds, double size, which is used by paper- 
hangers, may be melted in a saucepan, slightly thinned down, 
and drop black and whiting, previously mixed to the required 
tint, added. Two coats should be given with a stiff brush, the 
