THE TECHNICS OF CASEIN PAINTING. 77 



tion, this fixative has the property of drying quickly and not 

 too glossy. 



Another weatherproof varnish for preserving paintings- 

 is obtained, according to the patent of Gebruder Pilz, by 

 moistening collodion wool with methyl alcohol and then 

 dissolving it in a solution of camphor in alcohol containing 

 spirit of turpentine. 



Formaldehyde, too, has latterly been recommended as 

 an excellent means of rendering casein paintings insoluble 

 in water (see Formolactin). If a dry picture, painted with 

 casein paint, be exposed to the vapours of formaldehyde, the 

 agglutinant in the paint (casein, glue or albumen) quickly 

 becomes waterproof. 



Before closing the present chapter, it should be stated 

 that painting in the fresco and encaustic styles, as also at 

 secco and al sgraffito, can be performed with casein paints. 

 The methods elaborated by the Diisseldorf artist, Fritz 

 Gerhardt, on the basis of prolonged investigation and chem- 

 ical progress, are founded on a special preparation of the 

 substratum and on the use of specially prepared colours. 

 These include the fresco colours, marble colours (containing 

 marble dust and casein), encaustic colours (prepared with 

 wax and resin), the spike-oil colours and the universal 

 colours. The Gobelin colours (imitation Gobelins) and flag 

 colours, used for decorating flags, also belong to this class. 



Finally, tempera painting can also be performed with 

 casein paints. According to Beissier, a colour of this kind 

 can be prepared by mixing 



Dry casein powder 7 parts. 



Slaked lime 20 



Covering mass (chalk, ochre) .... 100 



Dextrin 8 



Soap powder 8 



and the necessary body colour. 



The wall pictures in the Hall of Fame (Ruhmeshalle) in 



