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1. Re: Why has JPEG format changed in recent versions of Photoshop?
Jeff Arola Jan 26, 2017 10:11 PM (in response to Mike Dallwitz)1 person found this helpfulAs an experiment try File>Save for Web>Jpeg and see if the older program reads those.
Likely photoshop is adding some metadata that the old program doesn't like.
Most like something that was added to the jpeg specifications, since jpegs from Zoner Photo Studio exhibit the same issue.
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2. Re: Why has JPEG format changed in recent versions of Photoshop?
Mike Dallwitz Jan 26, 2017 10:57 PM (in response to Jeff Arola)R_Kelly wrote:
As an experiment try File>Save for Web>Jpeg and see if the older program reads those.
Likely photoshop is adding some metadata that the old program doesn't like.
Most like something that was added to the jpeg specifications, since jpegs from Zoner Photo Studio exhibit the same issue.
Thanks for the suggestion. Unfortunately, it made no difference, even if I set 'metadata' to 'none'.
I think that metadata are unlikely to be the problem, because the files are OK when I add metadata (such as a description) in XnView.
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3. Re: Why has JPEG format changed in recent versions of Photoshop?
Jeff Arola Jan 26, 2017 11:10 PM (in response to Mike Dallwitz)Can you tell us what the name of the old program is?
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4. Re: Why has JPEG format changed in recent versions of Photoshop?
Mike Dallwitz Jan 26, 2017 11:33 PM (in response to Jeff Arola)R_Kelly wrote:
Can you tell us what the name of the old program is?
Intkey. It's available at http://delta-intkey.com/www/programs.htm. The CSIRO version is the one with the problem; the ALA port is OK (but requires Java).
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5. Re: Why has JPEG format changed in recent versions of Photoshop?
Jeff Arola Jan 26, 2017 11:33 PM (in response to Mike Dallwitz)According to this photoshop dropped one piece of data from the old JFIF standard to be compliant with the newer EXIF standard starting with photoshop cs5, so maybe that's the problem.
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6. Re: Why has JPEG format changed in recent versions of Photoshop?
Mike Dallwitz Jan 27, 2017 1:25 AM (in response to Jeff Arola)R_Kelly wrote:
According to this photoshop dropped one piece of data from the old JFIF standard to be compliant with the newer EXIF standard starting with photoshop cs5, so maybe that's the problem.
Thanks. It looks as though that's the problem.
However, the reasons given for not having an option to write the old format seem spurious. According to Chris Cox at the above page: "you cannot write a JFIF file that is EXIF compatible -- most EXIF compatible readers will choke on it (which is why we got so many complaints about Photoshop continuing to write JFIF)". I haven't found any modern apps that don't read both formats. No doubt there are some, but it would be up to users (the people creating the JPEG files) to decide which format was appropriate for their applications. In my case, the applications are Intkey and related programs, and Web browsers. The latter have no problems with the old format.
So, it seems I'll just have to use the workaround given in my original posting: use another program to do what Photoshop programmers consider impossible (or impractical). Fortunately, there are free programs around that do the job.
Incidentally, the reason I use Zoner is because of its good facilities for editing metadata, and for displaying selected metadata when viewing images ('slideshows'), though I still use Photoshop for editing the actual image content. In particular, I like to add descriptions (captions) and GPS data to my personal photos. As a result of investigating this problem, I stumbled across XnView, which is free, and has better facilities than the current Zoner for displaying captions in slideshows. If anyone is interested, there are some examples at http://www.dpreview.com/forums/thread/3478699#forum-post-51416126 - I suggest using the 'flat' view of the forum.
Thanks again for your help.
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7. Re: Why has JPEG format changed in recent versions of Photoshop?
Stephen_A_Marsh Jan 27, 2017 3:12 AM (in response to Mike Dallwitz)Mike can you please provide a link to a “good” file and a “bad” file via DropBox or similar file sharing sites, FTP etc?
If this is just metadata related, ExifTool should be able to come to the rescue, perhaps something like this to test if this creates a readable file or not:
exiftool -JFIF:XResolution='222' -JFIF:YResolution='222' -JFIF:ResolutionUnit='inches' 'Mac OS Path/to/MY BAD FILE.jpg'
Then if it does work, it would be “easy enough” to copy the values from the existing XMP tags into the JFIF tags.
Another approach worth trying is to get ExifTool to fully rebuild the entire metadata/file copying over the binary image data as required:
exiftool -all= -tagsfromfile @ -all:all -unsafe -icc_profile 'Mac OS Path/to/MY BAD FILE.jpg'
NOTE: The previous command line codes are from the Mac, on Windows simply change the single straight quote/foot mark ‘ to straight double quote/inch marks “ with the correct platform specific path to the file or top level folder.
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8. Re: Why has JPEG format changed in recent versions of Photoshop?
Mike Dallwitz Jan 28, 2017 4:17 AM (in response to Stephen_A_Marsh)Stephen_A_Marsh wrote:
Mike can you please provide a link to a “good” file and a “bad” file via DropBox or similar file sharing sites, FTP etc?
The following files are in http://delta-intkey.com/test\jpeg01.zip.
JPEG files tested in CSIRO Intkey
CS6.jpg - created in Photoshop CS6. Can't be read by Intkey.
The following files were converted from CS6.jpg by various programs. All can be read by Intkey.
CS6-CS4.jpg - Photoshop CS4
CS6-NConvert.jpg - NConvert (command-line image converter, http://www.xnview.com/en/nconvert/)
CS6-Paint.jpg - Paint (image editor included in Windows 10)
CS6-XnView.jpg - XnView (multimedia viewer, organizer and converter, http://www.xnview.com/en/)
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9. Re: Why has JPEG format changed in recent versions of Photoshop?
Stephen_A_Marsh Jan 28, 2017 5:19 AM (in response to Mike Dallwitz)Please let me know how these two test files go:
CS6_JFIF_Added.jpg = JFIF metadata added to file with the following ExifTool command (Mac OS formatted):
exiftool '-IFD0:XResolution>JFIF:XResolution' '-IFD0:YResolution>JFIF:YResolution' '-IFD0:ResolutionUnit>JFIF:ResolutionUnit' 'MAC OS/PATH/TO/CS6_JFIF_Added.jpg'
CS6_Rebuild.jpg = Metadata rebuilt using the following ExifTool command (Mac OS formatted):
exiftool -all= -tagsfromfile @ -all:all -unsafe -icc_profile 'MAC OS/PATH/TO/CS6_Rebuild.jpg'
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10. Re: Why has JPEG format changed in recent versions of Photoshop?
Mike Dallwitz Jan 28, 2017 5:39 AM (in response to Stephen_A_Marsh)CS6_JFIF_Added.jpg worked. CS6_Rebuild.jpg didn't.
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11. Re: Why has JPEG format changed in recent versions of Photoshop?
Stephen_A_Marsh Jan 28, 2017 2:33 PM (in response to Mike Dallwitz)2 people found this helpfulOK, so it is definitely the missing JFIF tags then.
Opening/resaving a JPEG is not best practice, due to the lossy compression.
ExifTool does not touch the binary image data when it alters the metadata and re-writes the file and it would be faster too.
You can easily swap out the path to the file with a path to a top level folder and add in the -r argument/command to recursively process multiple files in sub-folders under the top level folder. You can also restrict processing to only JPEG files too, if the top/sub folders contain other formats. Finally, it is also possible to exclude specific folders from be processed and to overwrite the originals rather than creating a duplicate file _original for safety.
Let me know if you wish to explore these options.