Relative histograms compare occurrences in event channels for a multi-channel data set for determining comparisons therebetween. One or more relative histograms are formed using relating functions applied to channels, preferably including a quotient between a first reference channel and a second channel and between the reference channel and at least a third channel. Preferably the relating functions generate values where a ratio and its reciprocal are symmetrical about an identity value. More preferably a data set is presented in a two-dimensional histogram for establishing the deviation of significant counts from an adjustment point which is preferably at the identity value. In practice, the relative histograms can be applied to correct tint in the red, green and blue channels of color images.