Archived from groups: comp.lang.postscript,comp.periphs.printers (More info?)
Hello -
The PS file below surprised me when I viewed the output under a
microscope. The gray bars are actually printed from a mix of CMYK.
However, if I comment out the line that prints the cyan lines, then
the gray lines get printed using only black.
I have some questions ...
1) Can someone explain why this is? I'm guessing it is related to
halftones, but my understanding of this topic is weak.
2) Can anyone suggest a way to get the printer to print the gray using
just black, while still printing the cyan?
FWIW, I am printing the file by copying it to the network name (i.e.
copy subset.ps \\server\printer).
Thanks in advance,
Paul
------------------------------- Begin included PS file --------------
%!PS-Adobe-3.0
%612 792 /letter setpagesize
/pagesave save store % Save VM state
100 dict begin
%%EndPageSetup
gsave mark
% Simple variables for later use
/str 500 string def % Dummy string for number -> string conversions
% Shorthand for setting primary colors
/cyan {1 0 0 0 setcmykcolor} def
/black {0 0 0 1 setcmykcolor} def
/black33 {0 0 0 0.33 setcmykcolor} def
% Called with one parameter - the LPI for this box
/VerRes {
50
% save state and set origin
gsave currentpoint translate
% Set scaling to inches to simplify
72 72 scale
% Set the linewidth
dup 2 mul 1 exch div setlinewidth
% loop for 1/2 inch, drawing the lines
0 exch 1 exch 2 div 1 sub {
% move to starting point for line
2 mul 0.5 add currentlinewidth mul 0 moveto
% draw and stroke a 1/2 inch line
0 0.5 rlineto stroke
} for
% restore state
grestore
} def
% Why are the black33 lines dithered in CMY - not made of black?
300 600 moveto black VerRes
340 600 moveto black33 VerRes
%380 600 moveto cyan VerRes
cleartomark end
pagesave restore % Restore VM state
showpage
-------------------------------- End included PS file ---------------
Hello -
The PS file below surprised me when I viewed the output under a
microscope. The gray bars are actually printed from a mix of CMYK.
However, if I comment out the line that prints the cyan lines, then
the gray lines get printed using only black.
I have some questions ...
1) Can someone explain why this is? I'm guessing it is related to
halftones, but my understanding of this topic is weak.
2) Can anyone suggest a way to get the printer to print the gray using
just black, while still printing the cyan?
FWIW, I am printing the file by copying it to the network name (i.e.
copy subset.ps \\server\printer).
Thanks in advance,
Paul
------------------------------- Begin included PS file --------------
%!PS-Adobe-3.0
%612 792 /letter setpagesize
/pagesave save store % Save VM state
100 dict begin
%%EndPageSetup
gsave mark
% Simple variables for later use
/str 500 string def % Dummy string for number -> string conversions
% Shorthand for setting primary colors
/cyan {1 0 0 0 setcmykcolor} def
/black {0 0 0 1 setcmykcolor} def
/black33 {0 0 0 0.33 setcmykcolor} def
% Called with one parameter - the LPI for this box
/VerRes {
50
% save state and set origin
gsave currentpoint translate
% Set scaling to inches to simplify
72 72 scale
% Set the linewidth
dup 2 mul 1 exch div setlinewidth
% loop for 1/2 inch, drawing the lines
0 exch 1 exch 2 div 1 sub {
% move to starting point for line
2 mul 0.5 add currentlinewidth mul 0 moveto
% draw and stroke a 1/2 inch line
0 0.5 rlineto stroke
} for
% restore state
grestore
} def
% Why are the black33 lines dithered in CMY - not made of black?
300 600 moveto black VerRes
340 600 moveto black33 VerRes
%380 600 moveto cyan VerRes
cleartomark end
pagesave restore % Restore VM state
showpage
-------------------------------- End included PS file ---------------
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