48 CASEIN. 



1 parts of colcothar. 



1 ,, of vine black. 



2 ,, of graphite. 



4 ,, of chrome green (limeproof). 



4 ,, of stone green. 



2 ,, of ultramarine. 



CASEIN-LIME COLOURS. 



Casein is an important material for tempera painting, and 

 the use of casein-lime colours for ordinary painting has been 

 long known. In consequence of the high price of linseed oil, 

 casein-lime colours are being much more generally used, and 

 great pains have been taken in improving this material to fit 

 it for use as a substitute for ordinary oil colours. If this 

 object has not yet been quite obtained, none the less, casein- 

 lime colours are now well established, and are being much more 

 frequently used as better methods of application are discovered. 

 It is very important in dealing with any kind of paint, to 

 know exactly how it should be applied. When casein-lime 

 colours were first put upon the market much disappointment 

 was caused by unsuitable methods of application, which tended 

 to set a strong prejudice against them. 



These colours cannot be recommended for every purpose, 

 and certainly not a substitute for oil colours in every case. 

 However, if prepared from suitable raw materials and applied 

 in a proper manner, they are perfectly satisfactory for certain 

 classes of work. The successful use of these colours depends 

 upon the formation of casein-lime lake produced by the two 

 components, casein and slake lime, in the presence of water. 

 The casein-lime lake binds the other mediums together. It is, 

 of course, necessary to choose materials which are not easily 

 affected by physical influences, and especially by atmospheric 

 conditions. 



Tempera colour contains about 85 per cent, of finest prepared 

 chalk, and about 10 per cent, of casein and 5 per cent, of 



