🚀 go-pugleaf

I have a PostScript diagram (generated by Corel Draw on a PC) which is used
to explain grey balance in teaching. There are two grey scales, one using
black and the other using equal CMY. The diagram is intended to show the
tints that can be expected. The colours were specified directly in CMYK in
Corel Draw.

The PostScript seems to have specifications of CMYK in it.

The printer cleverly detects that my colours could be substituted by black,
and prints two *identical* grey scales.

The printer (a Tek Phaser III PXi) comes with some software that allows you
to fiddle with things. Although clearly intended for the
dedicated-printer-hanging-off-the-back-of-a-PC type situation, it has
control D's in it to make the changes permanent.

I have tried inserting the code (without the control D's) into the Corel
PostScript file. This generates an error.

The original code is:

% Copyright (c) 1991, Tektronix, Inc.
%  Black Substitution (blacksub.ps):
%	Use this file to enable and disable black substitution.  The
%	   default is for black substitution to be enabled (true).
%   	Black substitution may be changed to either true or false.

%  Ctrl-d to flush any previous jobs @
%  Function is bracketed with startjob to unencapsulate and make
%     a change persistent.
true () startjob not
{/exitserver errordict /invalidaccess get exec} if
<< /PostRendering
EnhanceDetails
   << /BlackSubstitution false >>
>> setpagedevice   
false () startjob pop
%  Ctrl-d to end job @

I have indicated the control D's by @

Well I didnt want to make the change permanent either, so I ended up
putting:

<< /PostRendering
EnhanceDetails
   << /BlackSubstitution false >>
>> setpagedevice

into the Corel PostScript file.

I should perhaps point out that the printer is being used in a multi queue,
multi user environment, hanging off a VAX with print management by DECprint
Print Services. So, relying on sending sequential jobs is no good because
other users jobs might be interleaved. Also, the exitserver password has
been changed from the default. Also, I don't want to affect other users
jobs (or theirs to affect mine ;-) )

The print fails with:

%LPS-W-UNDEF, undefined: Name not known - offending command is
EnhanceDetails
%LPS-E-FLUSHING, Rest of Job (to EOJ) will be ignored

printed on an error page.

Any ideas, folks?  What am I doing wrong? How do I stop the printer doing
grey component replacement? How do I use these utilities in a multi-user
environment?

I will summarise any posted or mailed responses.

Chris		lilley@cgu.mcc.ac.uk