AND ITS APPLICATION TO THE DETERMINATION OF COLOUR SENSATIONS. 353 



TABLE VII. Chrome-yellow Pigment. 



(22.) Principles of Three-colour Photography. 



At the present time the accurate determination of colour composition in terms of 

 the three-colour sensations, of pigments, and transparent media, is of great practical 

 importance. There is now a large business carried on in the production of prints by 

 the three-colour process of photography, and up to the present time the colours 

 produced are, with rare exceptions, wanting in truth, probably owing to screens of 



VOL. ccv. A. 2 z 



