The case of the missing COMMENT (DOpus vs. ExifTool, round 10?)

Not for me; the 513 one shows no comment, whereas the 512 one does:

@auden

I’ve created a new thread “Image formats & metadata” in the Off-Topic forum to continue this discussion.

Now, that is interesting, and gave me an idea. I’ve verified that both files in that folder, as they already existed on my computer, continue to display their comments. But if I download that 7-zip from this thread, unpack it and check, the 513 does NOT display its comment. And if I then open Set Metadata for it, select/copy the full 513-character string from any of the other fields (DESCRIPTION, SUBJECT, TITLE) that contain it, paste to COMMENT and click on OK, the comment is then visible (via tooltip, dialog, panel, and DESCRIPTION field of lister file display). If you (and/or anyone else) don’t mind indulging me a bit more on this, I’d be interested in learning whether this is reproducible by anyone else following the same steps.

In any case, it seems that DOpus is not ignoring comments with 513+ characters under all circumstances, or at least not for me. I’d prefer that it never ignored them, but don’t recall ever having had any experience with iPhone photos packing all their metadata into Exif:XPComment, Exif:UserComment and/or Xmp:UserComment, even though I have dealt with some iPhone photos before. Is it something that should possibly be revisited?

If iPhone photos with all metadata pre-loaded into one or more comment fields are actually still a thing, could someone archive and upload one here for me to check out? My curiosity if piqued.

My guess is that the comment is being written to NTFS ADS metadata in the filesystem, as well as the EXIF data inside the file itself. That ADS would be lost when archiving the file, but also isn't subject to any length limits (since other tools don't do crazy things with it that cause problems with huge data chunks).

Wouldn’t you guys know if DOpus did that? Or are you saying something other than DOpus could be repsonsible?

Anyway, this is what the output of dir /r looks like for the two PNGs with their comments visible:

29-Mar-2021  17:16             8,152 2020-12-15 23;59;59 - General - xFGHI-00001 Invoice 1234567890 - 07 (512 ch).png
                               1,316 2020-12-15 23;59;59 - General - xFGHI-00001 Invoice 1234567890 - 07 (512 ch).png:SummaryInformation:$DATA
                                   0 2020-12-15 23;59;59 - General - xFGHI-00001 Invoice 1234567890 - 07 (512 ch).png:{4c8cc155-6c1e-11d1-8e41-00c04fb9386d}:$DATA
29-Mar-2021  17:11             8,168 2020-12-15 23;59;59 - General - xFGHI-00001 Invoice 1234567890 - 07 (513 ch).png
                               1,316 2020-12-15 23;59;59 - General - xFGHI-00001 Invoice 1234567890 - 07 (513 ch).png:SummaryInformation:$DATA
                                   0 2020-12-15 23;59;59 - General - xFGHI-00001 Invoice 1234567890 - 07 (513 ch).png:{4c8cc155-6c1e-11d1-8e41-00c04fb9386d}:$DATA

No expert on ADS here, and not completely sure what all that output is telling me. This page (“Introduction to Alternate Data Streams” at blog.malwarebytes.com) implies that $DATA should be the main file content, but I see two entities (streams?) ending with $DATA, one of which is listed as having a size of 0, for each PNG. If I attempt to read the contents of the non-0 ones (ending in SummaryInformation:$DATA), it just looks like gobbledegook to me. Curiously, the two SummaryInformation:$DATA streams are indicated as having the same size (1,316) in the output above, but when I read their content using Notepad++, one is said to have a normal text length of 1,724, while the other one is 1,726.

I used NirSoft’s AlternateStreamView to delete all of the alternate streams, but comments remain visible for both PNGs here, so it doesn’t look to me like ADS is the cause.

For images, I would not recommend using the 'Comment' field in the Extended Properties of the Metadata column. While it is a standard metadata field, it is not widely supported in software many people use for image management including software I use: Adobe Bridge, Adobe Lightroom Classic, and Photo Mechanic. I use the fields with the widest support so that I know the metadata I add will be visible to those using a wide range of software.

I hope this thread is the same issue as mine. My apologies if it's not.
I can't get Directory Opus to display comments that I know are there.
I now they are there, because ExifTool and ExifToolGUI show them.
FastStone Image Viewer also shows them.

Directory Opus Comment

ExifToolGUI Comment

Please zip and attach an example file with the issue.

Hi Leo.
As with all image metadata, it can contain a lot of information that people would not normally like to share.
So, I would rather not share the image publicly. Locations and much more. I don't know if people realise that when they share JPEG photos.

But if you can give me an alternative way of sending it to you, then I will do that.

Use a private message (or create an example image that doesn’t have sensitive data, assuming you have a workflow which can reproduce the issue for different images).

Done.

What software did you use to add the comment to the JPEG? I would be very interested in getting your sample file also.

I'm looking at this issue from the opposite side: Content entered into the DOpus Extended Properties > Comment field can be seen in ExifTool Exif XPComment and XMP-exif UserComment.
So, if you want to see your comment in DOpus, I'd suggest using a command in ExifTool or ExifToolGUI to copy the metadata from one of those 2 fields to the File - Comment field (as shown in your ExifToolGUI screenshot).
The text in the DOpus Comment field can be seen via File Explorer > File Properties, and is grouped with other fields associated with IPTC metadata. DOpus groups it with IPTC properties also (Ratings and Tags/Keywords). The problem is that only a few of Microsoft's photo-related metadata fields correlate with IPTC/XMP fields used by photo software, so I don't use File Explorer to enter or access photo metadata.
Perhaps the DOpus/File Explorer Comment field is widely used for other types of files?
In summary, if you work with photos and photo metadata a lot, I recommend only adding metadata to fields that correlate to fields accessible in the applications you depend on.

In that particular case in the screenshots above, JPEGmini Pro adds the comments when you shrink files sizes with it.

And as you can see from the screenshots, ExifTool, ExifToolGUI and FastStone Image Viewer can see them, but Directory Opus can't.

Protocol,
While I love DOpus and use it extensively for file management in my photo organizing work, I do not rely on DOpus for reading and/or writing photo metadata.
DOpus is not photo-focused, so I'm not at all surprised it does not read that metadata. Just because DOpus happens to have a field with the name/label 'Comment', does not mean it reads the metadata is in the field JPEGmini calls 'JPEG Comment' and that ExiftoolGUI calls 'File-Comment'. While field names may offer clues as to what metadata field they read, the only way to know for sure is to do your own testing. If you want help using a command in ExifToolGUI to move that metadata to a field DOpus does read, I can help you. I have made many different commands for ExiftoolGUI and use them to copy, move, or remove metadata for various fields.

Hi MegMac.

Below is an image of the DOpus logo.
I have shrunk the file size using JPEGmini Pro. You'll notice the JPEGmini Pro comment on line 13.
I have also included an image showing the comment in ImageGlass using the ExifTool plugin.

Protocol, I am trying to help because I work with photo metadata every day using many different applications. I do not work for Directory Opus. I understand that you can see your comment in a few applications. I am trying to you understand that not all applications show all metadata. Applications show the metadata fields the developers believe the users want and need to see - and DOpus does not show show that metadata field - which is not surprising as it is not commonly used.

Thanks for sending the file.

The comment also does not show up in Photoshop, Adobe Bridge, or File Explorer's Comments column or Properties dialog either.

(Telling File Explorer's Properties dialog to remove all personal data also does not remove the field from the file.)

It's using the old JPEG Comment field, rather than an EXIF tag or similar. My understanding is that JPEG Comment is rarely used/displayed these days, at least for anything useful (or if it is used for important information, the information is usually written into an EXIF tag as well). If Photoshop won't show the field then I think we can consider it obsolete.

However, you can use ExifTool Custom Columns to add columns to Opus based on data that ExifTool can see, which should give you a workaround if you need to see that data in Opus.

Thanks for looking into it, Leo.
I'll have a look at ExifTool Custom Columns.

I often check or edit common metadata fileds in Adobe Bridge. With Adobe Photoshop, one can view the exact same metadata fields as Adobe Bridge, however neither of those applications is truly designed for working with metadata. One can access roughly twice as many metadata fields with Adobe Lightroom Classic, so if you want to compare metadata, I recommend using Lightroom Classic.