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Bug #985

Exif Image.Description field is being used incorrectly

Added by Schnitzel Foo almost 5 years ago. Updated about 4 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Category:
exif
Target version:
Start date:
02 Sep 2014
Due date:
% Done:

100%

Estimated time:

Description

Spec 2.2: http://www.kodak.com/global/plugins/acrobat/en/service/digCam/exifStandard2.pdf
Spec 2.3: http://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf

According to the spec, the ImageDescription tag should actually contain the title of the image. Using digiKam the ImageDescription tag gets set to the description/caption, not to the title, and this causes issues with other software and online platforms (stock photography, etc).

" 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"

https://bugs.kde.org/show_bug.cgi?id=338753#c0

I edited the metadata like this:
http://i.imgur.com/YF5qPP7.png

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.exif.UserComment 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.

LibExiv2: 0.24
LibKExiv2: 2.3.1

Gilles Caulier asked me "can you report this problem to Exiv2 team to check if all is right or not," ergo this report.


Files

apg363.tif (2.38 MB) apg363.tif Schnitzel Foo, 02 Sep 2014 11:58
ArtistImpression.jpg (119 KB) ArtistImpression.jpg Robin Mills, 05 Sep 2014 06:08
IMG_2480.jpg (84.2 KB) IMG_2480.jpg Robin Mills, 05 Sep 2014 06:08
IMG_3876.jpg (86.5 KB) IMG_3876.jpg Robin Mills, 15 Sep 2014 07:09

History

#1

Updated by Robin Mills almost 5 years ago

  • Status changed from New to Assigned
  • Assignee set to Robin Mills
  • Target version set to 0.25

I never disagree with Gilles because he's such a nice guy.

I'm not sure this is a bug! The Exiv2 library provides the facilities to read/write/modify/add/delete tags in Exif, XMP and IPTC. The exact meaning of the tags is not of concern to the library. I personally use Picasa as my photo organiser and it has a "Make a caption!" feature which updates the tags: Iptc.Application2.Caption and Xmp.dc.description.

I think this requires a standards lawyer to say which tags should be updated by applications for interoperability. However I don't think Team Exiv2 has any opinion about the use of tags by applications. Phil or Andreas or another team member may wish to add helpful comments about this matter.

#2

Updated by Gilles Caulier almost 5 years ago

Robin,

The question is clear :

https://bugs.kde.org/show_bug.cgi?id=338753#c3

For me this Exif tag is a "Comment", not a "Title".

But i can be wrong here, this is why i ask to metadata specialists

Also, if somebody can report how Photoshop play with this tag to see if it's considerated as comment or title using image properties dialog, this will help.

Gilles Caulier

#3

Updated by Schnitzel Foo almost 5 years ago

Yes he is!

The spec states clearly that the tag is to be used for the title of the image. They made the unfortunate mistake of calling that tag "ImageDescription", but reading the spec clearly shows what it's intended for, and I believe Exiv2 should stick to this, as other software does, otherwise a mess is made. If you don't, how do I convince devs of other software who do stick to the spec to start misusing the tag? "Please treat this tag as the image caption even though the spec tells you not to because Exiv2 does that"? That won't fly. :)

#4

Updated by Gilles Caulier almost 5 years ago

Foo,

If you considerate Exif ImageDescription as a "title", i would to be sure that tags is used as well as a title by... Photoshop.

It's clear that photo world is dominated by Adobe currently. This is the reality. If Photoshop store comment and not title in this tag, it's clear that interroperability will the heel in the future, and i will receive a lots of bug reports about in digiKam area (and i don't want (:=)))).

Also the interpretation of this tag by other close source software will help a lots :

- AfterShot
- LightRoom
- Aperture
- Nikon NX
- Etc...

To resume : if you think that changing the vision of this tag by open source team will be difficult, changing the vision of this tag to close source company will be... impossible.

Gilles Caulier

#5

Updated by Robin Mills almost 5 years ago

Gentlemen:

I have (legal) access to Adobe: Lightroom, PhotoShop, Elements, Bridge. Apple: iPhoto, Aperture. Nikon: NX. Google: Picasa. I'll see how this is handled by those applications.

I have recently retired to England and awaiting our shipment from California. The iMac and DVDs with the software are in the consignment. The stuff has arrived in England, however we don't have a delivery date.

I'm still puzzled as to why this is being considered a bug in Exiv2. We read/write tags on demand. The relationship between an application user interface element labeled "Title" and the tag(s) updated are not the concern of Exiv2. However you're welcome to persuade me that I have mis-understood this topic.

#6

Updated by Gilles Caulier almost 5 years ago

Robin,

Consider this entry not as an Exiv2 bug. It's more a technical question which can have big incidence for the future with Exiv2 client application.

Gilles

#7

Updated by Robin Mills almost 5 years ago

Sure, Gilles. This is a "how do applications represent "Title" in meta-data?" Interesting question. And of course, now that I'm retired I have time to spend on this kind of thing.

Alison and I are very happy to be home in England. We have a lot of work to get our home back into perfect shape. We're both enjoying working together.

I'm very happy to be working on Exiv2 again. I don't feel I'm retired and out of the software world. I'm stimulated by contributing to Exiv2 and enjoying working with everybody on Team Exiv2.

#8

Updated by Schnitzel Foo almost 5 years ago

I have to say, so far my involvement with Exiv2 devs consists of two issue reports, this one included, and straight away I felt that you are great people :)

Gilles (or Caulier? Sorry, I can't tell which one is your name :P ) yes you have a very good point there! I'm holding my thumbs that Lightroom/Photoshop go by the spec, as that would make life easier :)

#9

Updated by Robin Mills almost 5 years ago

I worked at Adobe for 16 years. I will not be surprised to learn that every application (even the Adobe applications) do something a little different. However, when my kit arrives from California, we'll find the answer.

Thanks for being so complimentary about Team Exiv2. We are a happy band. Andreas, Gilles and Brad have created a very nice library of good quality C++ code. And we've added engineers in Build (Robin) / Test (Nehal) / EPS (Volker) / Video (Abhinav and Mahesh) / Internet (Tuan) / Metadata (Niels) / Release (Shawn). And Phil often speaks up on the Forum. We aim to please and I believe we do.

Thanks for saying something so nice. It's very motivating.

#10

Updated by Robin Mills almost 5 years ago

Good News. Our stuff from California is to be delivered next Wednesday 10 September. We're having a garden party on September 13 for friends, family and neighbours. So once that's over, I'll deal with this. All Exiv2 users are welcome at the party of course. The garden has had a huge makeover and we've built a summer house.
Artist's Impression (PhotoShop):

Today (still to be painted)

#11

Updated by Schnitzel Foo almost 5 years ago

Seems that I actually lived some 20km from you in Kingston until last year :) Now I'm in Sweden. Enjoy the party :]

#12

Updated by Thomas Beutlich almost 5 years ago

@Robin: When you do tests with the above mentioned tools please use some Arabic/Hebrew/Kyrillic title name and comment/description to also check how tools perform on Unicode data. Thanks.

#13

Updated by Robin Mills almost 5 years ago

This is a really tough area for me. Because I'm a native English speaker, I am puzzled by the whole Unicode business. I appreciate its importance, however I find it almost impossible to design tests for this. There have been several topics about this raised on the forum. As the majority of Team Exiv2 live in Asia, maybe I can persuade one of them to take responsibility for this part of our code and test suite. http://dev.exiv2.org/issues/848

#15

Updated by Alan Pater almost 5 years ago

According to MWG (Metadata Working Group) Guidelines

Description
defines the textual description of a resource's content. 
Also known as "user comment”, "caption”, "abstract” or "description”. 
Exif ImageDescription, IPTC Caption, and XMP (dc:description) are mapped together.

From section 5.2 of http://www.metadataworkinggroup.com/pdf/mwg_guidance.pdf

I don't see any guidelines on "Title".

#16

Updated by Schnitzel Foo almost 5 years ago

This MWG spec is in direct conflict with the JEITA and CIPA specs. What do we do?

#17

Updated by Robin Mills almost 5 years ago

What do we do?

We stick to the plan! My iMac arrived from California on Wednesday. In the next day or two I will investigate how different applications deal with this and report back. We'll chat some more and then decide what's best.

We had a great time at the party on Saturday. Summer House is beautifully painted in colours of the Flag of Scotland.

#18

Updated by Robin Mills almost 5 years ago

  • Status changed from Assigned to Resolved

Method

1 Start with a photo "Boy.jpg" with the Caption (Iptc.Application2.Caption) "Jonas"

2 Create Directories for each application:

drwxr-xr-x+ 4 rmills  staff      136 Oct  6 20:31 Picasa/
drwxr-xr-x+ 3 rmills  staff      102 Oct  6 20:27 iPhoto/
drwxr-xr-x+ 3 rmills  staff      102 Oct  6 20:23 AdobeBridge/
drwxr-xr-x+ 3 rmills  staff      102 Oct  6 20:23 LightRoom/
drwxr-xr-x+ 3 rmills  staff      102 Oct  6 20:20 PhotoShopElements/

3 Copy Boy.jpg into the application directories:

find . -type d -exec cp Boy.jpg {} \;

4 In each application, use the "Title" feature to assign the "Title"

"the boy stood on the burning deck" 

5 Extract the metadata from Boy.jpg

exiv2 -pa Boy.jpg | sort > Boy.txt

6 Extract the metadata for each application

for d in $(find . -type d); do d=${d:2} ; if [ ${#d} != 0 ]; then exiv2 -pa $d/Boy.jpg | sort > $d.txt ; fi; done

7 Compare original Boy.jpg with each "Titled" application image

for i in *.txt; do echo --- file=$i --- ; diff Boy.txt $i ; done | grep -e Jonas -e 'burning deck' -e file=

Results

$ for d in $(find . -type d); do d=${d:2} ; if [ ${#d} != 0 ]; then exiv2 -pa $d/Boy.jpg | sort > $d.txt ; fi; done
$ ls -alt *.txt
-rw-r--r--+ 1 rmills  staff   4.1K Oct  6 22:08 iPhoto.txt
-rw-r--r--+ 1 rmills  staff   5.6K Oct  6 22:08 AdobeBridge.txt
-rw-r--r--+ 1 rmills  staff    11K Oct  6 22:08 Lightroom.txt
-rw-r--r--+ 1 rmills  staff   8.7K Oct  6 22:08 PhotoShopElements.txt
-rw-r--r--+ 1 rmills  staff   4.0K Oct  6 22:08 Picasa.txt
-rw-r--r--+ 1 rmills  staff   3.9K Oct  6 20:28 Boy.txt
$ for i in *.txt; do echo --- file=$i --- ; diff Boy.txt $i ; done | grep -e Jonas -e 'burning deck' -e file=
--- file=AdobeBridge.txt ---
> Iptc.Application2.ObjectName                 String     33  The boy stood on the burning deck
> Xmp.dc.title                                 LangAlt     1  lang="x-default" The boy stood on the burning deck
--- file=Lightroom.txt ---
> Iptc.Application2.ObjectName                 String     33  the boy stood on the burning deck
> Xmp.dc.title                                 LangAlt     1  lang="x-default" the boy stood on the burning deck
--- file=PhotoShopElements.txt ---
> Iptc.Application2.ObjectName                 String     33  the boy stood on the burning deck
> Xmp.dc.title                                 LangAlt     1  lang="x-default" the boy stood on the burning deck
--- file=Picasa.txt ---
> Iptc.Application2.Caption                    String     33  The boy stood on the burning deck
> Xmp.dc.description                           LangAlt     1  lang="x-default" The boy stood on the burning deck
--- file=iPhoto.txt ---
> Iptc.Application2.Caption                    String     33  The boy stood on the burning deck
$ 

Conclusions:

  1. Adobe applications are consistent
  2. Adobe, Google (Picasa) and Apple (iPhoto) are not consistent
  3. No application updates Exif.Image.ImageDescription

I'm going to mark this issue "Resolved". This issue belongs in the application or standards domain and not the Exiv2 library.

Summer House Update

Finished and totally awesome. All Welcome and we will fly the Flag of Visitors. Our first visitors were from the United States.

#19

Updated by Schnitzel Foo over 4 years ago

Hello

Sorry, I didn't get notified of the update to this issue.

I'm not clear on what the conclusion is. Should programs treat Exif.ImageDescription as the image description or as the title? I need this worded clearly when I forward the link to multiple other projects which use Exiv2.

#20

Updated by Robin Mills over 4 years ago

  • Subject changed from Exif ImageDescription field is being used incorrectly to Exif Image.Description field is being used incorrectly

My conclusion is that this is not an issue for Exiv2 and I can be of no further assistance to you.

#21

Updated by Schnitzel Foo over 4 years ago

Thank you.

#22

Updated by Robin Mills about 4 years ago

  • % Done changed from 0 to 100
#23

Updated by Andreas Huggel about 4 years ago

  • Status changed from Resolved to Closed

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