18 Responses to “Writer’s block”

  1. Gilles Caulier Says:


    The only way to support DNG files in writting mode under linux, and especially with digiKam is to have the Adobe DNG SDK published under Open-Source compatible license and with full linux support. Currently the SDK can be only compilled under M$ and MAC.


    Why Adobe do not publish this SDK under BSD licence like it have done with XMP SDK ???


    DNG is a tiff based file format, but use a JPEG lossless compression on image data supporting 16 bits color depth.
    We cannot use libtiff for that. This compression algorithm is only available on DNG SDK. Also look licence in DNG SDK, you will understand why this code is not backported outside in opensource…

    Alternative to this JPEG Loss Less compression is to use a linear storage of decompressed RAW image data. I have already done few code in this way for digiKam, but size of DNG file in this case are very huge. This is have no sence to use it instead original RAW image data from camera witch provide a small files size…

    About metadata, digiKam team work on Exiv2 library project to support tiff writting mode. So the future is here. Writting DNG metadata will be possible (and normally with all RAW files format based on TIFF spec)

    About XMP metadata support in digiKam, current implementation dedicaced to KDE4 support it !


    Gilles Caulier
    digiKam project coordinator

  2. vivosz Says:

    Thanks for the explanation. i did not know that the dng sdk was released with that kind of license.

    I’m quite disappointed, because if i understood your comment right, there won’t be a solution soon to write dng-s.

    Anyway, i think it’s high time for me to try digiKam 0.9.3-beta 2 (currently i’m running 0.9.2).

    Thanks again, all the best


  3. vivosz Says:

    Thanks, but I already downloaded it yesterday. Currently i’m having some issues with configuring, hopefully will solve it soon.

  4. Gilles Caulier Says:

    2 blogs entries about new features. More will become later…



    Gilles Caulier

  5. vivosz Says:

    Finally successfully installed digiKam 0.9.3.!
    To tell you the truth I haven’t tested the app thoroughly so far, but i will definitely do it in the next few days!

  6. Gilles Caulier Says:

    About IPTC/XMP metadata, with KDE4 digiKam and kipi-plugins port, XMP is supported everywhere. A new XMP editor have been implemented, and IPTC editor have been very improved.

    Look screenshots at this url :


    Gilles Caulier

  7. vivosz Says:

    Hmmm…. I think i will have to download the latest version from svn 😉

  8. Caulier Gilles Says:

    Warning. XMP support is only available with KDE4 implementation (trunk in svn)

    KDE3 branch do not support XMP. Perhaps i will backport code from KDE4 to KDE3 at 0.9.4 release.

    I don’t recommend to use the KDE4 yet in production. Code still not finalized or uncomplete. Stable and robust code still in KDE3 branch…


  9. J Dickon Glanville Says:

    I think I need some clarification on a comment …

    In Gilles Caulier first comment, he says that the DNG SDK needs to be released with an open-source license in order for DNG to be supported. Is that true? Does the SDK need to be licensed, or just the specification? Ie: if the spec is openly publicized/licensed, then anyone can write tools that can write DNG files that meet the specification.

    Gilles, am I missing something?

  10. vivosz Says:

    Well, I don’t know much about licensing issues, nor about the using/implementing of sdk-s, so looking forward reading Gilles’ clarification.

  11. Gilles Caulier Says:

    Well, It’s simple. Look DNG sdk web page, licensing is readable :


    From an open-source user (or developper), you accept or do not accept the licence ???

    This one is fully uncompatible with open-source world of course…

    This situation been the same with XMP SDK in past. Since one year now Adobe have changed the restrictive licence to BSD:


    My question is why Adobe do not use BSD licence with DNG SDK ???

    Gilles Caulier

  12. J Dickon Glanville Says:

    Vivosz, according to the Wine AppDB, the Adobe DNG Converter works 100% under Wine.


  13. Gilles Caulier Says:

    yes, its work (:=)))… but it a little bit old. New RAW file formats from recent camera are not supported. This program sound like not updated.

    For example, digiKam (witch use dcraw internally) supports around 280 RAW file formats. Adobe DNG converter only 150…

    Like i use always RAW files in my photo workflow (Minolta Dynax 5D), i will explain how i work :

    – Picture are imported in digiKam in RAW file (MRW format)
    – RAW decoding in set to 16 bits color depth.
    – Color Management is set on using Minolta Camera ICC profiles.
    – I use digiKam Light Table to choose the right pictures from my collection.
    – When i want to edit a picture, i use digiKam image editor witch supports 16 bits color depth and can fix 90% of picture problems ! Gimp only support 8 bits color depth and is unadapted to photo editing (i hate Gimp interface) !!! For advanced edition, i use krita witch support 16 bits color depth too.
    – In digiKam image editor, when picture is corrected, i save it to PNG format. PNG support 16 bits color depth, use a lossless compression algorithm, support ICC color profile, and can save EXIF/IPTC and XMP metadata. It’s a perfect file format for photograph under LINUX (better than TIFF). All my pictures are stored in RAW (backup) and PNG (editing).
    – For publishing, i use of course JPEG (8 bits color depth only, not lossless, take a care). For that, Batch converter from digiKam (a kipi-plugin) is used to transform PNG to JPEG (ImageMagick is used in background). Nothing is lost, excepted color depth of course. JPEG are temporary files.

    Gilles Caulier

  14. vivosz Says:

    >J Dickon Glanville Says:
    >November 27, 2007 at 2:09 am e
    >Vivosz, according to the Wine AppDB, the Adobe DNG >Converter works 100% under Wine.

    Thanks, I know. My problem is not to convert my photos, but rather how to develop them after conversion 🙂

  15. vivosz Says:

    Gilles, where does digiKam store the data about the alterations a user make on raw files? In its database or in sidecar files? I was unable to find any info about it in the documentation.

    The biggest reason of my insisting on DNG is because it contains the information about raw file editing. It’s portable. When i open it in another editor/cataloger/whatever, it looks the same and i won’t loose the previous work on the file.

  16. Gilles Caulier Says:

    >Gilles, where does digiKam store the data about the alterations a user >make on raw files? In its database or in sidecar files? I was unable to >find any info about it in the documentation.

    digiKam do not yet store pictures alteration list somewhere (Image Editor Actions List). There is a file in bugzilla about this subject, and it’s planed to host this list in :

    – Database to be able to perform search for ex, and to apply same changes in others pictures (by drag & drop for ex.). This require a changes of Database witch is already done in digiKam for KDE4 (0.10.0)
    – In pictures metadata : XMP (as a duplicate of list from database). This require XMP support witch is implemented in digiKam fro KDE4. Also, currently Exiv2 library do not yet support TIFF file writting mode. It’s planed to do it for next major release (>0.16.0). Like this we will be able to save list in RAW file based on TIFF spec.
    – In Sidecar file if picture do no support metadata, as an export option. Not yet implemented. Using XMP metadata is always the better way about portability…

    >The biggest reason of my insisting on DNG is because it contains the >information about raw file editing. It’s portable. When i open it in >another editor/cataloger/whatever, it looks the same and i won’t loose >the previous work on the file.

    Really. Each photo management program witch host alteration list in RAW pictures use a private TAG for that. There is no interoperability issue here. For ex, try to use Nikon RAW capture program, and edit a NEF image. All changes are store in NEF file as an editor action list in a private area…

    DNG will not solve interoperability issue here. Sure, it will give a standardized way to add metadata to a RAW file (DNG is standardized, all others RAW file no). But the editor actions list data added aren’t standardized. At least, if program is right, it will use XML format (XMP based)…


  17. vivosz Says:

    > But the editor actions list data added aren’t standardized. At least, if program is right, it will use XML format (XMP based)…

    Well i didn’t know that editor actions list, or alteration information is not standardized in DNG.
    But, after thinking it over, no two applications have similar toolkit (except the apps based on dcRaw, naturally), and even if they woud have the same options, they would likely to implement slightly different algorythms to achieve similar results.
    In the end, even if metadata on actions were standardized, opening an edited raw image in an other editor would result in a slightly different image.

    It seems to me now, that the raw workflow’s foundation stone is to choose an application wisely, and stick to it till the end.

    I understand that i will need to change my workflow, maybe abandon dng. But then how will i be able to rebuild my catalog of my several thousand dngs under linux?

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