THE TECHNICS OF CASEIN PAINTING. 75 



be remixed by stirring or shaking, but any skin that forms 

 should be thrown away. 



Casein paint that has partly or completely dried in the 

 can is unfit for use, and it is therefore necessary to guard 

 against this by covering the surface with water or closing 

 the cans airtight. 



If the medium becomes frozen in winter it should be 

 slowly re warmed over a water bath and then stirred up well. 



The application of casein paints is performed in the fol- 

 lowing manner : 



After the ground has been suitably prepared, the outlines 

 are sketched with crayon and coloured in, any excess of 

 crayon being wiped off with a soft clean cloth. 



The well-thinned paint is then laid on, as light in colour 

 as possible. The oftener the coating is repeated the more 

 attractive the effect produced, whereas, if the paint is too 

 thick the effect is diminished and it readily tends to peel off, 

 this being especially the case with dark colours containing 

 an excess of the casein medium, though it may also occur 

 when the other extreme is in question. This must be tried 

 and modifications made accordingly before beginning the 

 actual work of painting. 



Both wide bristle brushes and fine long sable brushes are 

 used. If, when the work is finished, some of the tones do 

 not harmonise, they can be modified by working over the 

 whole portion. 



Thus, if one tone be too light and warm or too bright, 

 it is worked over with ivory black alone, other alterations 

 being made with deep colours, reduced to a thin paste with 

 water and quickly laid on with the brush. In these opera- 

 tions the greatest cleanliness is necessary, both with the 

 colours and with the cans and other utensils. 



To paint frescoes on canvas, a rough canvas is coated 

 with undiluted casein preparation and painted in quite wet 



