Bug 223232

It's cleary an Exiv2 library stuff. Which Exiv2 version you use with digiKam ? Go to Help/Component info for details.

Try to use Exiv2 command line tool with your DCF files to see if you can identify Color Profile.

Gilles Caulier

I'm using libexiv2 0.18.2.

This is a quote from a developer on the LittleCMS mailing list (where I brought up this issue before filing a bug here):

On Sun, Jan 17, 2010 at 7:32 AM, Larry Reeve <larry@polybytes.com> wrote:
> The first image is in "DCF Colorspace". This can be seen from the following
> entries in the EXIF:
>
> Color Space:    Uncalibrated
> WhitePoint X:   0.31
> WhitePoint Y:   0.33
> Chromaticity Red(X):    0.64
> Chromaticity Red(Y):    0.33
> Chromaticity Green(X):  0.21
> Chromaticity Green(Y):  0.71
> Chromaticity Blue(X):   0.15
> Chromaticity Blue(Y):   0.06
> YCbCrCoefficient 1:     0.30
> YCbCrCoefficient 2:     0.59
> YCbCrCoefficient 3:     0.11
>
> A DCF aware application sees this information and processes the image
> accordingly (which means use an Adobe RGB profile).

And a further reply when I asked if this was an application-level or library-level issue:

On Sun, Jan 17, 2010 at 5:03 PM, Larry Reeve <larry@polybytes.com> wrote:
> LCMS does not have anything to do with the color space defined in the EXIF
> block of a JPEG file. There is no embedded profile. It is up to the
> application using LCMS to evaluate the color space definitions in the EXIF
> and take the action to load and use an Adobe RGB profile if it is needed.
> The DCF Optional Color Space (see paragraph 6.2 of of JEITA CP-3461 "Design
> rule for Camera File system DCF Version 2.0") defines the values that should
> alert an application to take this action:
>
> Color Space:    Uncalibrated
> WhitePoint X:   0.31
> WhitePoint Y:   0.33
> Chromaticity Red(X):    0.64
> Chromaticity Red(Y):    0.33
> Chromaticity Green(X):  0.21
> Chromaticity Green(Y):  0.71
> Chromaticity Blue(X):   0.15
> Chromaticity Blue(Y):   0.06
> YCbCrCoefficient 1:     0.30
> YCbCrCoefficient 2:     0.59
> YCbCrCoefficient 3:     0.11

Here are two files straight from my camera as examples. One is in sRGB colorspace, the other is in Adobe RGB colorspace. Both conform to the DCF 2.0 specification. Both have their color space detected properly in commercial applications.

sRGB:
http://lh3.ggpht.com/_HAZjMzZWrtc/S05qk1yxBOI/AAAAAAAABC0/5kXGfiIIF7s/d/GORE3360.JPG

Adobe RGB:
http://lh6.ggpht.com/_HAZjMzZWrtc/S05qkb7KkYI/AAAAAAAABCw/oPJ80XXYH-Y/d/_GOR3359.JPG

So far I have been provided with test images, all of which use a more traditional way of defining color space (simple tags, usually only sRGB or AdobeRGB). You are the first one to mention this DCF spec here, which should explain why it's not supported.

If the spec PDF is not available, can information be found anywhere about the tags relevant for color management?

I've found a PDF document that outlines the relevant changes in DCF 2.0 (as opposed to 1.0), but it doesn't go into detail. It can be found here:
http://www.cipa.jp/exifprint/contents_e/01exif_e/ExifDCFsummary_E.pdf

I also have a copy of the full DCF 2.0 specification here as a PDF, but I'm no expert on copyright and stuff. I don't know if I can redistribute it. I found it laying around on the web, I didn't purchase it or anything. It says:

© 2002 by the Japan Electronics & Information Technology Industries Association All rights reserved. No
part of this standard may be reproduced in any form or by any means without prior permission in writing
from the publisher.

Nothing there about giving the PDF file to someone else... but just about anyone can find it by typing "DCF 2.0" in google and looking at one of the top 5 results.

Thanks, I got it.
I will have a look at this, not immediately, but keep it on my TODO list for after 1.1

I downloaded the two sample files, sRGB and AdobeRGB are properly detected. Please reopen if you have files where this is not the case with recent versions of digikam and Exiv2.