I had a hard time figuring out where the software chain I used in my workflow is broken. I traced it down to digiKam using the EXIF:ImageDescription field for the image description. While this seems perfectly fine, reading the Exif specification reveals that the unfortunate circumstance is that this field is actually reserved for the title! CIPA DC- 008-Translation- 2012 " ImageDescription A character string giving the title of the image. It is possible to be added a comment such as "1988 company picnic" or the like. Two-byte character codes cannot be used. When a 2-byte code is necessary, the Exif Private tag UserComment is to be used. Tag = 270 (10E.H) Type = ASCII Count = Any Default = None" One ends up with a long image description where the title should be, and when you use other software which stick to the spec this causes problems and more work. I edited the metadata like this: http://i.imgur.com/YF5qPP7.png exiftool -G -s -a -m -u -args apg363.tif | egrep "Description panel|Title panel" -EXIF:ImageDescription=Description panel..ASCII Kolor stitching | 3 pictures | Size: 599 x 512 | Lens: Fisheye | RMS: 2.23 | FOV: 73.76 x 49.34 ~ 28.90 | Projection: Planar | Color: None | -EXIF:UserComment=Description panel..ASCII Kolor stitching | 3 pictures | Size: 599 x 512 | Lens: Fisheye | RMS: 2.23 | FOV: 73.76 x 49.34 ~ 28.90 | Projection: Planar | Color: None | -XMP:ImageDescription=Description panel..ASCII Kolor stitching | 3 pictures | Size: 599 x 512 | Lens: Fisheye | RMS: 2.23 | FOV: 73.76 x 49.34 ~ 28.90 | Projection: Planar | Color: None | -XMP:Title=Title panel. -XMP:Description=Description panel..ASCII Kolor stitching | 3 pictures | Size: 599 x 512 | Lens: Fisheye | RMS: 2.23 | FOV: 73.76 x 49.34 ~ 28.90 | Projection: Planar | Color: None | -XMP:UserComment=Description panel..ASCII Kolor stitching | 3 pictures | Size: 599 x 512 | Lens: Fisheye | RMS: 2.23 | FOV: 73.76 x 49.34 ~ 28.90 | Projection: Planar | Color: None | -IPTC:ObjectName=Title panel. -IPTC:Caption-Abstract=Description panel..ASCII Kolor stitching | 3 pictures | Size: 599 x 512 | Lens: Fisheye | RMS: 2.23 | FOV: 73.76 x 49.34 ~ 28.90 | Projection: Planar | Color: None | As you can see, according to the spec this is wrong, as EXIF:ImageDescription should be "Title panel." Any chance this could be fixed in 4.3.0? Reproducible: Always
As i know, we don't change anything about Exif comment management since a long time into libkexiv2 interface (and in whole digiKam in fact) I suspect more a bug introduced in Exiv2 shared lib. After all this lib perform all background metadata management. Q : what's give Exiv2 CLI tool instead to use Exiftool ? After that, can you report this problem to Exiv2 team to check if all is right or not. They know better all standard to use about metadata. Gilles Caulier
In other words, you want mean that in your example you want to see : -EXIF:ImageDescription=Title panel. Right ? Gilles Caulier
Reading spec : "A character string giving the _TITLE_ of the image." Yes, this depand how you interpret "title" here. "... It is possible to be added a _COMMENT_ such as..." It's clear that it can be interpreted as a comment. And i think that usual people use Exif "Description" tags as a comment about the image. Q : how other tools, which differentiate "Title" and "Comment" from GUI manage this tag exactly ? For ex, Photoshop which can be considerated as a reference here ? Gilles Caulier
LibExiv2: 0.24 LibKExiv2: 2.3.1 @ comment 1: exiv2 -pa ~/test_images/apg363.tif | egrep "Description panel|Title panel" Exif.Image.ImageDescription Ascii 168 Description panel. Iptc.Application2.ObjectName String 12 Title panel. Iptc.Application2.Caption String 167 Description panel. Xmp.tiff.ImageDescription LangAlt 1 lang="x-default" Description panel. Xmp.dc.title LangAlt 1 lang="x-default" Title panel. Xmp.dc.description LangAlt 1 lang="x-default" Description panel. Xmp.exif.UserComment LangAlt 1 lang="x-default" Description panel. I will attach the file. @ comment 2: exactly, that is as the spec has it. @ comment 3: I don't know what Photoshop does, I don't have it.
Created attachment 88530 [details] Image tagged by digiKam-4.2.0
Reported: http://dev.exiv2.org/issues/985
Dr Slony, What we can conclude following review by Exiv2 team from bug 985 ? Gilles Caulier
Caulier: I'm actually not sure as far as Exif.ImageDescription is concerned. I asked Robin if he could clarify: http://dev.exiv2.org/issues/985#note-19
Robin Mills over at exiv2 concluded that Adobe applications DO NOT USE the Exif.ImageDescription field. For Title Adobe uses: xmp.dc.title. MWG (Metadata Working Group) guidelines map Exif ImageDescription, IPTC Caption, and XMP (dc:description) together as "Description: the textual description of a resource's content. Also known as "user comment”, "caption”, "abstract” or "description”." i vote for following the MWG guidelines.
Alan, This is how digiKam work currently now (following MWG rules), or i missing something ? Gilles Caulier
Yes, agreed. Digikam is following the MWG guidlines.