🚀 go-pugleaf

Joey,

A RIP is a raster image processor (the firmware that converts the
postscript commands to actual dots that the device puts down on the
page/sheet of film/plate/etc.).

The Windows version of FM does not generate its own postscript, but
rather relies on the Windows operating system GDI (graphic device
interface) to generate the postscript output. Unfortunately, Microsoft
only sees the world in RGB, so all CMYK colours (except colours in EPS
graphics files that get passed through untouched to the postscript
stream) get converted to RGB. This is not good for press work, since
the colours have to be converted back to CMYK. To further complicate
things, the RGB to CMYK conversion is not a linear process (i.e. you
do not get the same values as you start with going from one colour
space to the other and then back again). 

There are third-party tools that allow you to correct the RGB output.
One such tool is ColourChameleon, which works on the postscript file
to correct the colours before conversion to PDF. Other tools such as
PitStopPro or Quite-a-Box-of-Tricks let you adjust the colours in the
PDF file afterwards.

When you finally get the fixed-up PDF created, you're using what's
called a composite workflow (all of the colours are together in the
file). The RIP then separates these colours to give you your colour
plates for press-work.

FM can work with colour in another manner, called a pre-separated
workflow, where it will create separate pages or plates for each of
the colours on output. The output file is then run straight out to
film and the RIP doesn't do any separations. However, one small
caveat. These pre-separated files are actually RGB, so if you don't
inform your print shop of this, they may not set the RIP properly and
it will automatically try to transform the RGB images of the separate
colour plates into CMYK plates as well (you do the math as to how many
pieces of film that you could be on the hook for!).

Colour from FM works quite well, but you have to be aware of the
pitfalls of not knowing how to properly do it.

I hope this helps.