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

Graeme Gill graeme at argyllcms.com
Sat May 12 01:46:20 PDT 2012

Michael Sweet wrote:

> There are (typically) two cases where you want to turn off color management:
> 1. Printing of targets for profiling. 2. Printing from an application that provides its own
> color management.
> Both require an off switch; whether this is exposed to the user, application, or both is an
> implementation choice.  I personally believe that it should only be exposed to applications
> since not all applications will work well (if at all, depending on the device color space) with
> color management turned off.  Moreover, providing UI gives the false impression that no color
> conversions will be done - quite the contrary, if the driver needs CMYK but the app normally
> produces documents using RGB/sRGB, then the RIP filter will need to perform some default
> conversion to provide the raster data to the driver in the correct color space.


If an application/RIP does this for the "No color management" mode, then it's
behaving poorly, since it is not complying with the mode and is actively
deceiving the user. It should do one of of two things in this mode:
1) Reject any job that contains colors other than the native decide color space,
or, if you want it to be a bit more forgiving, 2) Reproduce non-native device
color spaces in an easily recognisable wrong way, ie. by running then though
an inverted "wave" LUT with inverted colors.

I don't agree with naming this mode "Printer Profiling", since it assumes a certain
usage that may not be true, and gives no hint as to what the mode actually does.

A more accurate name would be something like "native device colorspace only".

> Both should also require a way for the application to query the device color space (Gray, RGB,
> K, CMYK, DeviceN, etc.) used for particular print settings selected by the user.

Yes, if a device has more than one native device colorspace (ie. by sub-setting it's
inkset), there should be a way to profile it.

> from all applications.  The current state-of-the-art on Windows and Mac leaves a lot to be
> desired. Aim higher!


Graeme Gill.

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