[gs-devel] GS & ImageMagick - making CMYK work...

[Russell Lang]

Dan,

> Thanks for the info.  Do you know any applications that will
> display pam format for more than 4 components?

I just realised there is another problem. The pam format 
specifies TUPLETYPE of BLACKANDWHITE, GRAYSCALE and RGB.  
The man page for pam doesn't mention CMYK but this would be 
an obvious extension.  Beyond this, there is no clear way 
to specify the colours of additional layers. Perhaps this 
could be put in comments, or perhaps the TUPLETYPE could be 
set to the CMYK approximations of each separation colour.  

Russell

> -----Original Message-----
> From: Russell Lang [mailto:gsview at ghostgum.com.au]
> Sent: Friday, June 07, 2002 1:27 AM
> To: Leonard Rosenthol
> Cc: gs-devel at ghostscript.com; Ray Johnston; Dan Coby
> Subject: Re: [gs-devel] GS & ImageMagick - making CMYK work...
> 
> 
> Leonard and others,
> 
> The pbmplus format has been extended in netpbm to have a
> format pam (portable arbitrary map format, man 5 pam),
> which can contain an arbitrary number of components.  It
> would be worthwhile adding a pam device to ghostscript
> which supports CMYK initially, but can be extended to
> DeviceN when this is added to ghostscript.
> 
> I will look at adding a pam device to GNU and AFPL
> Ghostscript.  I hope Dan can extend this for DeviceN.
> 
> Russell
> 
> 
> From:           	Ray Johnston <ray at artifex.com>
> To:             	Leonard Rosenthol <leonardr at lazerware.com>
> Copies to:      	gs-devel at ghostscript.com
> Subject:        	Re: [gs-devel] GS & ImageMagick - making
> CMYK work...
> Date sent:      	Thu, 06 Jun 2002 22:27:01 -0700
> 
> > Dear Leonard,
> >
> > The "bitcmyk" device is a 4 component device that by default is 1-bit
> > per component (4-bit CMYK), but this can be switched at run time to
> > 4-bit per component or 8-bit per component (16-bit CMYK or 32-bit
> > CMYK) using this -dGrayValues= command line option. GrayValues default
> > is 2 (1-bit) and can be set to 16 (4-bit per component) or 256 (8-bit
> > per component).
> >
> > The result is a 'raw' bitmap, so there is no compression and no
> > header, but this may give you what you need.
> >
> > Note that you can also set this device parameter at run time using
> > the 'setpagedevice' operator. For example,
> >
> > 	<< /GrayValues 256 >> setpagedevice
> >
> > will dynamically switch to 8-bit per component mode. The 'bit'
> > device is similar in that it produces monochrome (1-bit up to
> > 8-bit) and the 'bitrgb' device produces RGB.
> >
> > Regards,
> > Ray Johnston
> > Artifex Software Inc.
> > ________________________________________________________________________
> >
> > Leonard Rosenthol wrote:
> > >
> > > Hello all.
> > >
> > > I am one of the maintainers of ImageMagick
> > > (http://www.imagemagick.org), and am in need of some recommendations
> > > from you folks to make the link between the products even better.
> > >
> > > For those that don't know, ImageMagick uses GS to rasterize
> > > PS/EPS/PDF files for later processing by our raster image tools.
> > > This works great (and has for many years now!), PROVIDED that the
> > > user wants RGB output (since we use  -sDEVICE=pbmraw).
> > >
> > > However, we are seeing more and more users wanting to keep their CMYK
> > > source documents come across as CMYK to IM, rather than going
> > > CMYK->RGB->CMYK.
> > >
> > > We've tried a couple of standard devices that appear to support CMYK
> > > output, but haven't had any luck :(.
> > >
> > > So, can anyone recommend an output device that we can use to get the
> > > intended results?  One that could output CMYK _OR_ RGB, based on the
> > > source document would be great, but we'd be willing to switch that on
> > > our end if necessary.
> > >
> > > On a related note, we believe a MIFF output device was once created,
> > > but doesn't appear in the lists anymore?  Does anyone know what
> > > happened to it?
> > >
> > > Leonard
> > > --
> >
> > --------------------------------------------------------------------------
> -
> > > Leonard Rosenthol
> <mailto:leonardr at lazerware.com>
> > >                                              <http://www.lazerware.com>
> > > _______________________________________________
> > > gs-devel mailing list
> > > gs-devel at ghostscript.com
> > > http://www.ghostscript.com/mailman/listinfo/gs-devel
> > _______________________________________________
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> > gs-devel at ghostscript.com
> > http://www.ghostscript.com/mailman/listinfo/gs-devel
> 
> 
> Russell Lang                   gsview at ghostgum.com.au
> Ghostgum Software Pty Ltd      http://www.ghostgum.com.au/
> 
> 
> 


Russell Lang                   gsview at ghostgum.com.au
Ghostgum Software Pty Ltd      http://www.ghostgum.com.au/