Here is the info I got from Brian. A demo of his software can be downloaded from
http://www.iridientdigital.com/I suggest we run some experiments on this.
Edmund
Hi Edmund,
You should be able to do what you describe below with RAW Developer already.
RAW Developer can read the DNG color matrix metadata embedded in a DNG file and use it to provide the color rendering information and color match to any specified output ICC profile you may have on your system (sRGB, AdobeRGB, etc). This color rendering is selected by choosing "DNG Style Color Rendering (use file metadata)" from the Input Profile menu and is only available with DNG format files.
RAW Developer can alternately use a "default" set of DNG color matrix metadata which generally would be loaded and stored from an existing DNG file, but this "default" can also be manually generated (uses an XML based preferences file). This allows DNG style color rendering to be used with camera manufacturer provided RAW formats without forcing the user to convert all of their files to DNG format. This color rendering is selected by choosing "DNG Style Color Rendering (default)" from the Input Profile menu.
RAW Developer can also use ICC based input profiles along with an option pre-ICC profile color matrix (typically used by the high end digital back manufacturers where they have a "generic" or "neutral" or "no color correction" matrix and then ICC profiles handled the generic color space (Leaf for example uses ProPhoto RGB for their "generic" color space to "look" or "style" color rendering as in "portrait" or "product"). The advantage of a pre-ICC profile matrix here is that you can then share your "look" ICC profiles among different backs or cameras. This color rendering is selected by choosing appropriate ICC profile from the Input Profile menu. The ICC profiles must be stored in one of the standard Mac OS X locations such as the /Library/ColorSync/Profiles folder.
Adobe allows some of these options (items 1 and 2) already with LR/ACR and this can be overridden by the user so that they would get the camera makers color matrix values instead of Adobe's defaults. In many cases there may only be a single color matrix provided (Adobe's), but there can be multiple "DNG metadata calibrations" available in some cases say one or more from Adobe (generally varying based on version of ACR) and then "embedded" which would be the actual DNG file metadata as stored by the camera manufacturer or 3rd party tool, Adobe's DNG Converter, etc.
To demonstrate the above the Leica M8 is a nice example as Leica natively uses DNG format for the M8, Adobe has provided multiple "default" color matrix options with different versions of ACR and DNG files are readily available for download direct from the manufacturer here:
http://en.leica-camera.com/service/downloa...der_cameras/m8/
When you open an M8 DNG file into ACR click on the Camera Calibration tab. At the top of this pane is a "Camera Profile" popup menu which should have the following options:
1) "Embedded" this is the actual DNG file metadata in the case of the M8 this information is written by the camera itself. In some cases this metadata may be changed due to camera firmware versions. This metadata could also be embedded by a 3rd party program, for example a DNG based camera profiling program that computed color matrix values based on images of color reference charts.
2) "ACR 4.4" this is the "default" color matrix metadata as provided by the most recent release of ACR.
3) "ACR 3.6" this is the "default" color matrix metadata as provided by a previous release of ACR.
Similar to how you can store custom camera defaults in RAW Developer with "Make Settings Camera Default" you can also store custom defaults in ACR with "Save New Camera RAW Defaults". By default with most cameras RAW Developer uses ICC input profiles. By default with most cameras ACR uses the most recent ACR version of the color matrix, but for some camera models where Adobe has not established its own color matrix values (such as Ricoh which also natively uses DNG format in its cameras) the "Embedded" option will be the default and will use the manufacturer provided values.
ACR/LR don't support ICC based input profiles so item (3) isn't currently possible. The DNG specification does currently support the concept of embedded ICC profiles in addition to the color matrix metadata, but I believe all current programs (including RAW Developer) that support DNG will ignore the ICC profile metadata. I'm only currently aware of any camera manufacturers or software that support DNG format and which use the DNG ICC profile tags at this time.
Brian Griffith
Iridient Digital
- Hide quoted text -
The problem is that LR/ACR does not implement these abilities of DNG.
What we aim to show is that one can use DNG to allow the user *if he
wants* to get a rendering that has been defined by the camear
manufacturer rather than the Raw converter author.
Edmund
On Mon, Apr 14, 2008 at 10:28 PM, edmund ronald <edmundronald@gmail.com> wrote:
The proposal is to implement DNG's abilities incrementally:
1. Read in a Matrix from the file meta-data and apply it in lieu of the profile.
2. Apply an "out" profile on top of the matrix
3 Apply an In profile instead of the matrix, and an Out profile.
4 will be done externally at first: Compute the matrix in (1) by means
of a spectral sensitivity curve and an illuminant curve.
Edmund
