[Openicc] GoSoC 2011: CPD and Color Management

Kai-Uwe Behrmann ku.b at gmx.de
Mon May 2 00:02:41 PDT 2011

Am 01.05.11, 19:49 -0400 schrieb Robert Krawitz:
> On Sun, 01 May 2011 23:04:56 +0200, Jan-Peter Homann wrote:
>> For a CPD based workflow we need a mechanism to synchronize media / driver settings for following use cases:
>> - driver vendor provides profiles in the standard installation
>> - media vendor provides standard profiles for his media for a given driver
>> - profiling service offers profiles based on printed testcharts
>> - user is makes his own profiles
>> Technically this could be solved in two way
>> 1) Export and Import of medie / driver settings with an attached ICC-profile
>> - The driver must allow to createand export  a media / driver setting with an assigned profile for each setting
>> - During import of such a setting incl ICC, the consistency between driver setting a profile is guaranteed.
>> 2) Integrating the driver setting into the ICC-profil through ICC dictType Metadata Registry
>> - In this case, the driver must be able to be setup through one file, which can be driver specific.
>> If Gutenprint can be setup by such a file, the Gutenprint-Team can register a Gutenprint specific dictType Metadata Registry entry at the ICC.
>> - We than need a mechanism to integrate the Gutenprint dictType entry into a printer profile through e.g. Oyranos, g-c-m / colord, ArgyllCMS or other tools.
>> - The CUPS xxxtoRaster filters need the possibility to embed the outputprofile into the raster-file for the driver
>> - the driver needs the possibility to read the embedded profile from the raster-file and extract the dictTyp entry for automatic setup of the driver.
>> ****
>> From my perspective approach 2) - ICC dictType is more universal and
>> smart compared to echange of vendor specific driver setups with
>> assigned ICC profiles. It can espcially combined with all main
>> scenarios of colormanagement in the printing chain:
> I think I'd also prefer #2; it would require no integration between
> Gutenprint and ICC profiles.
> Gutenprint currently provides a way to serialize a settings object
> into an XML representation, and to import that XML representation.
> It's currently only used internally, but it's a public API that I
> believe would be well suited to this purpose.  I don't understand how

could you provide a link to that API for reference?

> the higher level color stuff works well enough to do the layering work
> (and I don't have time to architect it), but I'd be happy to work with
> someone who does.

Could you locate the needed architectural work inside the following 

>> 2a) application based printer colormanagement
>> The printer-profile is configured in the application and the application delivers prematched raster-data for the printer. This is. eg.g the case with Inkscape today.
>> The only enhancement the Inkscape team has to do, would be to embedd the printer profile in the raster-file fro the printer, which is a quite simple task.
>> 2b) OS based printer colormanagement
>> Under LINUX this handled through cupsICC and different xx_to_Raster filters like e.g. GhostScript or Poppler. The main task here would be to embedd the printer profile in the raster-file fro the printer, which is a quite simple task.
>> 2c) driver based colormanagement
>> In this case the driver allows to create printing queues with setups bith for a source an target profile. The user has one GUI for driver configuration and queue / colormanagement setup. CUPS does only rasterization and no color transformations.
>> 2d) Usage of a colormanagement framework like e.g. Oyranos or colord / g-c-m
>> As the profile to device match is encoded into the profile itself, the usage of Oyranos or colord/g-c-m is simplified for the printing path.
>> I would be very glad if the GoogleSoc project could implement the
>> dictType approach based on Gutenprint.

As the dictType is the main integration point for device ICC profiles 
in Oyranos, that will surely play a big role in Josephs GSoC project.

>> As I´m a member of the ICC, I would take care, that the Gutenprint
>> dictType Metadata will be registerred at the ICC.

kind regards
Kai-Uwe Behrmann
developing for colour management 
www.behrmann.name + www.oyranos.org

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