Re: LaserWriter color management ABC
Re: LaserWriter color management ABC
- Subject: Re: LaserWriter color management ABC
- From: Henrik Holmegaard <email@hidden>
- Date: Tue, 9 Jan 2001 21:27:50 +0100
Chris Murphy <email@hidden> wrote:
Opening the resulting PostScript file confirms this. So I'm not exactly
sure what you mean by none of the Laserwriter controls apply whe printing
from an app that generates it's own PostScript.
Device independent color workflows require an assumed source color
space in the right format for the given CMS technology. For ICC
workflows it's ICC device profiles, and for in-RIP workflows it's
always a CSA (whether for CIELab which requires a CSA (!), or RGB, or
CMYK, or grayscale). If no CSA is present for an object in the PS
job, then you can't get the channel values in the object referenced
to CIEXYZ, and no in-RIP conversion happens. If you don't assign an
assumed source ICC profile in an ICC color server, then no conversion
happens either. Simple as that.
The in-RIP workflow assumes that the application which writes
PostScript will write a CSA for each object in the PS job.
Applications that support a CMYK imaging model write their own
PostScript, and don't use the RGB QuickDraw printing pipeline. These
applications write to the LaserWriter driver in pass-through mode,
and the color settings in the driver don't apply to them. This
doesn't mean that they can't put CSAs and CRDs in their PostScript,
but only that this isn't accomplished using the LaserWriter driver
controls. It is accomplished by the application that writes the
PostScript job.
The RGB printing pipeline works both with firmware QuickDraw printers
/ drivers, and with PostScript printers when you want to use one and
also want to print from QuickTime PictureViewer, SimpleText, MacWrite
Pro, or Eudora which don't have a CMYK imaging model and don't write
their own PostScript. In this case you can use the LaserWriter driver
color matching commands, as described in the ABC.
(Hmm...I almost thought you'd not bounce this and leave the ball on
the floor -:).)