[Openicc] Gutenprint team requests CM-off for a print queue be provided as a maintained engineering facility.

Gerhard Fuernkranz nospam456 at gmx.de
Sun May 13 03:22:36 PDT 2012

Am 12.05.2012 01:32, schrieb edmund ronald:
> Why can't every future version of ghostscript for Linux systems have our CM-off switch?

Well, even older ghostscript versions (e.g. 7.x) already did provide this opportunity (via regular Postscript and PDF mechanisms, i.e. either by turning the UseCIEColor flag off, and/or by setting the DefaultXXX color space resources to /DeviceXXX (i.e. to identity), which disables the remapping of /DeviceXXX colors). Therefore it is rather a matter of the ...toraster print filters to invoke ghostscript correspondingly (granted that they make use of ghostscript at all).

[ Btw, IIRC, the built-in default value of ghostscript's DefaultXXX color space resources did change in the past, so it may be a good idea anyway if the ...toraster filters would not rely on ghostscript's built-in defaults, but always set up the desired DefaultXXX resources explicitly in oder to get consistent results across different versions of gs (and maybe some other parameters too, whose built-in defaults may change with version, like transfer functions, black generation & UCR functions). ]

Additionally to "CM-off" it may also be necessary to turn off linearization curves in order to print linearization test charts. As far as I know, linearization curves are in the current print pipeline not applied by ghostscript via transfer functions, but directly applied in the Gutenprint driver. So turning them off is a matter of passing corresponding parameters to the driver.

Best Regards,

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