HP PCL/PJL reference - PCL 5 Comparison Guide

2-18 Printer-Specific Differences ENWW
Table of Logical Operations
Table 2-6, Logical Operations (ROP3), shows the mapping between
input values and their logical operations. Note that the logical
operations are specified as RPN (reverse polish notation) equations.
Here is a key to describe what the Boolean Function values mean;
Note Since logical operations are interpreted in RGB space (white = 1 and
black = 0) rather than in CMY space (white = 0 and black = 1), the
results may not be intuitive. For example, ORing a white object with a
black object in RGB space yields a white object. This is the same as
ANDing the two objects in CMY space. It must be remembered that
the printer operates in something similar to a CMY space and inverts
the bits and reverses the order.
S = Source a = AND
T = Texture o = OR
D = Destination n = NOT
x = EXCLUSIVE OR