ROSS. DESIGN AS A SCIENCE. 



3G3 



wlii(;h intervals give the greatest satisfaction to the sense of vision. 

 The attempt to reach cotichisions on the question of color-contrast, by 

 comparing colors in different values and of different intensities, is per- 

 fectly futile. 



The greatest possible interval in the color scale is, as I have said, the 

 interval of 180°, the interval between opposite colors of the circle. 

 These colors are known as complementaries. In the scale of six colors 

 there are three pairs of complementaries: red and blue, purple and 

 green, yellow and violet. For the sake of brevity we will indicate the 

 colors by their initial letters : R for red ; Y for yellow ; G for green ; 

 V for violet ; B for blue ; P for purple ; N for neutral. For the scale 

 of neutral values we have already a terminology. Complementary 

 colors, when tones of the same value and intensity are mixed together, 

 neutralize one another, approximately. The relation of the complemen- 

 tary colors may, therefore, be stated in this form : — 



Observe that the complementaries balance, one against the other, on 

 the intermediate neutral, when of the same value and intensity. The 

 degree of intensity may be represented by the distance or space between 

 the sign of the color and the sign of the neutral which separates it from 

 its complementary. The greater this distance the greater the intensity. 

 Ill the statement which follows, yellow and violet and purple and green 

 are all equally intense, but the red and the blue are twice as intense : — 



Y 



■N — V 



N B 



N — G 



The complementaries balance on the intermediate neutral, other things 

 being equal, at equal distances from one another on the straight line 

 connecting their centres. But in the arrangement 



]{ — N 



the neutral being the ground-tone, the red being only half as intense as 

 the blue, it will have to be moved to twice the distance, unless its 



