ON THE RELATION OF OPTICS TO PAINTING. 131 



colours may, without injury, be juxtaposed, which 

 indeed are so similar as to look like varieties of the 

 same colour, produced by varying degrees of light and 

 shade. Thus, upon scarlet the more shaded parts ap- 

 pear of a carmine, or on a straw-colour they appear 

 of a golden yellow. 



If we pass beyond these limits, we arrive at un- 

 pleasant combinations, such as carmine and orange, or 

 orange and straw-yellow. The distance of the colours 

 must then be increased, so as to create pleasing com- 

 binations once more. The complementary colours are 

 those which are most distant from each other. When 

 these are combined, such, for instance, as straw-colour 

 and ultramarine, or verdigris and purple, they have 

 something insipid but crude ; perhaps because we are 

 prepared to expect the second colour to appear as an 

 after-image of the first, and it does not sufficiently 

 appear to be a new and independent element in the 

 compound. Hence, on the whole, combinations of 

 those pairs are most pleasing in which the second 

 colour of the complementary tint is near the first, 

 though with a distinct difference. Thus, scarlet and 

 greenish blue are complementary. The combination 

 produced when the greenish blue is allowed to glide 

 either into ultramarine, or yellowish green (sap green), 

 is still more pleasing. In the latter case, the com- 

 bination tends towards yellow, and in the former, 



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