USING PROLOGUE.PS/EPILOGUE.PS WITH COLOR SEPARATIONS

When Distilling color PostScript files, sometimes separation color spaces (spot colors) can 
be mapped to process colors, losing any defined custom colors. To remedy this, ensure that 
the "Distill with prologue.ps/epilogue.ps" option is turned on in the Distiller Job Options, 
Advanced dialog (or in UNIX, by adding the -includebookends on option to the command line). 
Then, move the prologue.ps/epilogue.ps files from the Distillr:XTras:high_end folder into 
the same folder as the Distiller application. For more information about using prologue.ps 
and epilogue.ps files in general, see the Acrobat Distiller 3.0 Online Guide.

Here is a more technical description of why this occurs. PostScript files that conform to 
the PostScript Level 1 conventions for color separations use an operator called 
setcustomcolor, which gets defined by the application which receives/imports the file. 
The default definition is to convert custom colors into their process color equivalents 
using the setcmykcolor PostScript operator. This means that the separations information is 
lost, which may be preferable if the file is not to be later separated.

If on the other hand, one wants separations, then a definition of setcustomcolor that uses 
separation color spaces in PostScript is needed. The Distiller will then preserve that 
information, and it can be printed from Exchange, either as PostScript Level 2 separation 
color spaces, or as a PostScript Level 1 file conforming to the conventions for color 
separations. To use this definition of setcustomcolor which retains the custom color 
definitions, one must Distill files using the prologue.ps and epilogue.ps files described 
above. 
