The theory behind GCR is that whenever dots of yellow, magenta, and cyan are present in the same color, there is a gray component to that color. That is, if the smallest of the three dot values were to be removed from the color, together with appropriate amounts of the other colors in order to produce a neutral gray tone, then that gray tone could be replaced with a dot of black. for example, to produce a brown a balance of 30% cyan, 40% magenta, and 55% yellow could be used. By using GCR a similar color could be produced by removing the cyan and printing 35% magenta, 45% yellow, and 20% black (see figure 1). The 3-color separation would require 125% of an ink film while the GCR separation would require only 100%