Hi All, There seems to be some confusion regarding the relationship between ICC profiles and the color encoding in an image or document file.   The basic rule is - when any digital color object is created it must be labeled by the creating device or by a person who knows the characteristics of the creating process.  The label must indicate the current actual color space, i.e., color space encoding = white point, primaries, gamma, digital encoding rule, etc.  This can be thought of as the "source" encoding. Such source color encoding definition information should be created by scanners, cameras, and authoring applications. The label must match the actual encoding, e.g., an Adobe RGB label can be linked to an image encoded in Adobe RGB. No other label can be associated with that image.  RGB color spaces may sound similar - but in fact the well known RGB color spaces [color encodings] are quite distinct from each other.  The same is true for the various different CMYK color space encodings. A color space encoding label may be a tag that gives the name of a standard color space, such as sRGB or Adobe RGB, or the label can be an ICC profile.  An ICC profile can provide an unambiguous definition of any color space, whether it is standard or proprietary. If the label is a tag that gives the name of a standard color space, then a profile for that color space optionally does not need to be carried with the content - it can be retrieved and applied whenever the content is used. Alternatively, both a color space name tag and a profile can be attached. Again in this case both must match exactly to the actual contents of the color space encoding. A color management color conversion operation requires both a source profile [the current encoding] and a destination profile [ the next encoding representation - typically for a display or print device]. Any system that handles color documents or images needs functionality to: a. Honor profiles that come attached to content [image, document] files. These profiles answer the question - What are the current color encodings in the file? Complex documents can contain multiple source profiles - each linked to a different content object. Note: an output profile may be included in certain PDF/X files  - that profile indicates the intended output color encoding and is used as the destination profile in a color management conversion operation. b. Provide for retrieval of standard profiles [actual std and defacto std] to be used when content files use the color space label approach. [e.g., profiles provided through links on the ICC website: www.color.org] c. Define an RGB 'default' interpretation policy [i.e., default source label]  to be used when no real label is present. Note that color management results will only be correct when the guess is correct. There are many legacy files incorrectly labeled as 'deviceRGB' that have to be handled. d. Define a CMYK 'default' interpretation policy [i.e., default source label] to be used when no real label is present. Note that color management results will only be correct when the guess is correct. There are many legacy files incorrectly labeled as 'deviceCMYK' that have to be handled. e. Never drop - always carry through - color space encoding labels of all kinds. Note - a profile that is carried with an image file or content file must always take precedence over a "standard" profile of the same name.  The embedded profile might have been edited for the particular use. f. Provide for selection/retrieval of a destination profile for a color management color conversion operation - this can be an RGB profile or a CMYK profile, etc. f. With Version 4 profiles, use the Version 4 profile - profile ID field - to check whether two profiles are the same. Specifics for each of these requirements vary depending on image and document formats and color management tools. My apologies if this is review for most of you.  It seemed from some comments that a background statement might be helpful. Best regards, Ann McCarthy Lexmark CPD Imaging Systems Engineering "To every complex problem there is a simple solution - and inevitably it is wrong"   HL Mencken <table width=100%> <tr valign=top> <td> <td>Sven Neumann <sven@gimp.org> Sent by: openicc-bounces@lists.freedesktop.org 07/05/2006 04:31 PM <td>                To:        Hubert Figuiere <hfiguiere@teaser.fr>         cc:        OpenICC Liste <openicc@lists.freedesktop.org>         Subject:        Re: [Openicc] Open Source compatible AdobeRGB profile</table> Hi, On Wed, 2006-07-05 at 16:29 -0400, Hubert Figuiere wrote: > > What about http://www.eci.org/eci/en/040_colour_standards.php ? Their > > profiles could serve as an alternative for AdobeRGB, couldn't they? > > How does it help if the pictures are in the AdobeRGB colorspace? Users would still have to download the AdobeRGB profile from Adobe, of course. But at least they would have a reasonable RGB profile to work with. And long-term it might make AdobeRGB less important. Sven _______________________________________________ openicc mailing list openicc@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/openicc