44 CASEIN. 



manner: 50 parts f water are added by degrees to 100 

 parts of the powder, with constant stirring, which is con- 

 tinued until the mass is homogeneous and free from 

 lumps. The mass is then covered with a thin layer of water 

 and left for about three-quarters of an hour, after which it is 

 again stirred, and more and more water is added until a work- 

 able paint is obtained, of about the same consistency as oil 

 paint. When intended for coating rough surfaces the paint 

 should be a little thinner, but may be thicker when used to 

 replace oil paint for smooth surfaces. It should be used 

 without delay, as it is liable to set hard in a comparatively 

 short time, becoming unfit for use in about twelve hours. 



Hence it is not advisable to make up any more of the 

 paint than can be used the same day. If, after the paint 

 has remained some time in the vessel, it skins over, this 

 skin must be removed. Made up white paint of this kind 

 can be afterwards coloured by mixing up the pigments 

 with water to, a pap, and stirring this into the paint until 

 uniformly incorporated therewith. In this case also it is 

 desirable to try a little of the paint before using it on the 

 work in hand. 



The application of the paint and the preparation of the 

 surface are the same as mentioned in the chapter on casein 

 painting. A solid and clean surface is essential to success. 

 As the paint will adhere to any solid surface, such as lime, 

 plaster of Paris, or cement, plaster, brick, metal, stone or 

 wood, as well as on canvas without any preparation, all that 

 is necessary is to clean the surface of dust and dirt to begin 

 painting at once. The paint is laid on with a clean, but 

 somewhat worn brush, free from grease, the paint working- 

 better than with a new brush. It is laid on fairly thick and 

 spread by working the brush about, this method ensuring 

 a better hold on the substratum and giving a more uniform 

 coating free from spottiness. In other respects the opera- 



