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

[Michael Sweet]

Chris,

On May 11, 2012, at 6:09 AM, Chris Lilley <chris at w3.org> wrote:
> On Thursday, May 10, 2012, 2:34:06 PM, Graeme wrote:
> 
> GG> Richard Hughes wrote:
>>> People printing targets are in the
>>> 0.00001% of our userbase, and I'm not sure we want GUI controls for
>>> that small number of people. Can't we just document a terminal command
>>> that would turn off all printer CM completely?
> 
> Richard, at LGM we had a conversation where you said you wanted CM to be as simple as possible for most people and I said that was fine as long as the simplicity did not prevent people who needed higher quality from doing their work.
> 
> Not being able to switch off colour management on a given queue means not being able to profile the device on that queue, so seems to fall into that category.

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.

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.

For #2, we should also require a way for the application to query the default profile for a printer that has been registered for particular print settings. This is because otherwise users will end up using completely different profiles (or having to register them N times) when printing from different applications.

The goal should *not* be to propagate what has been done before just because it is the workflow that is most familiar.  Instead, design a system and UI that allows color professionals to print targets and generate profiles, and for all users to make use of profiles in a consistent way from all applications.  The current state-of-the-art on Windows and Mac leaves a lot to be desired. Aim higher!

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Michael Sweet, Senior Printing System Engineer, PWG Chair