HP 4 FAMILY - Manual (Page 55)

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;
S = Source a = AND
T = Texture o = OR
D = Destination n = NOT
x = EXCLUSIVE OR
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 remem-
bered that the printer operates in something similar to a
CMY space and inverts the bits and reverses the order.
Printer-Specific Differences 2-19