OOF2: The Manual
Name
ColorNorm — Ways of measuring the difference between two colors.
Description
ColorNorms
are different ways of measuring
the difference between Colors
.
They're used in the Burn
pixel selection algorithm.^{[39]}
The difference between two colors in the L1
norm is the average of the absolute values of the differences of
their red, green, and blue values. That is, it's the difference
of the gray value equivalents of the colors.
The difference between two colors in the L2
norm is the square root of the sum of the squares of the
differences of their red, green, and blue values.
Values

L1
: The sum of the absolute values of the RGB differences. 
L2
: The square root of the sum of the squares of the RGB differences.
^{[39] } Burn could have been defined using the ColorDifference classes instead, but it wasn't, for historical reasons.