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When does EXIF data get lost?

 
 
Terry Pinnell
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      11-12-2004, 12:25 PM
I suspect I'm being unduly optimistic in hoping this is a question
with a relatively simple answer!

When I browse folders of old photos, I would often like to know the
precise date and time they were taken. But the EXIF data is missing
for many. Presumably EXIF info must have existed for *all* of them
when I first downloaded the DSC000xxxx.jpg images from my Sony
Cybershot DSC-1 to my PC, but editing has destroyed it?

Does anyone have or know of an up to date list of all operations by
specific graphic editing programs which result in such destruction of
the EXIF data please, so that I can make a point of avoiding them?

Am I right that although Operation X in Program A might preserve EXIF,
Operation X in Program B, or Operation Y in Program A (etc) might
destroy it? IOW, it's something of a mess? If so, I guess the safest
bet is to keep a copy of those originals, or at least a compact list
of some sort of their EXIF dates, for future reference if it's
inadvertently lost?

--
Terry, West Sussex, UK

 
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Mike Fields
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      11-12-2004, 02:26 PM
While I don't have a list (would like to see one though!), some
editors do lose the EXIF data while others preserve it. Then,
there is the argument I have heard that if the image is modified,
the EXIF is no longer valid so should be discarded -- my pref
would be to see an editor that when you modify an image, leaves
the original EXIF data, but adds a comment in the comment
field "modified and the date". Some editors advertise they
preserve the EXIF data others are silent. Get a utility like
irfanview (free) http://www.irfanview.com and use it to see
what the EXIF data is (good program for other stuff too).
I guess the bottom line is, yes, it is a crap shoot and you need
to test all of your software used in modifying images to see
which ones trash the EXIF data for you. I also like to keep
the originals -- disk space is cheap these days (and make
backups, but that is another thread in this group !! )

mikey

"Terry Pinnell" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> I suspect I'm being unduly optimistic in hoping this is a question
> with a relatively simple answer!
>
> When I browse folders of old photos, I would often like to know the
> precise date and time they were taken. But the EXIF data is missing
> for many. Presumably EXIF info must have existed for *all* of them
> when I first downloaded the DSC000xxxx.jpg images from my Sony
> Cybershot DSC-1 to my PC, but editing has destroyed it?
>
> Does anyone have or know of an up to date list of all operations by
> specific graphic editing programs which result in such destruction of
> the EXIF data please, so that I can make a point of avoiding them?
>
> Am I right that although Operation X in Program A might preserve EXIF,
> Operation X in Program B, or Operation Y in Program A (etc) might
> destroy it? IOW, it's something of a mess? If so, I guess the safest
> bet is to keep a copy of those originals, or at least a compact list
> of some sort of their EXIF dates, for future reference if it's
> inadvertently lost?
>
> --
> Terry, West Sussex, UK
>



 
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JHoffnagle
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      11-12-2004, 03:43 PM
Older versions of Photoshop, ACDSee, and Paintshop Pro that were not
EXIF "aware" would not preserve the EXIF data when the image was saved
after editing/converting/etc.

The best way to test your various applications is to take an original
image, rename it, then edit/change it, then save it. Open it again to
see what hapens to the EXIF data, and document the results. I'd also
recommend updating/replacing any application that trashes the EXIF
data fields - in the long run you won't regret it.

Huffy


On Fri, 12 Nov 2004 12:25:57 +0000, Terry Pinnell
<(E-Mail Removed)> wrote:

>Am I right that although Operation X in Program A might preserve EXIF,
>Operation X in Program B, or Operation Y in Program A (etc) might
>destroy it? IOW, it's something of a mess? If so, I guess the safest
>bet is to keep a copy of those originals, or at least a compact list
>of some sort of their EXIF dates, for future reference if it's
>inadvertently lost?


 
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Bruce Lewis
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      11-12-2004, 04:00 PM
JHoffnagle <(E-Mail Removed)> writes:

> I'd also recommend updating/replacing any application that trashes the
> EXIF data fields - in the long run you won't regret it.


I think Huffy is right on with that comment.

However, if you have some application that you can't update or still
trashes EXIF information, another step you can take is to rename the
files with the date/time they were taken. This can be done in a batch
with the free jhead program. You can also rotate according to your
orientation sensor with jhead if you've also installed jpegtran.

Download an example of jhead/jpegtran usage from here:

http://img.ourdoings.com/windows.html

(I got the impression you were on Windows. If you're on Linux there's a
link from there to the Linux version.)

After you download it, look at the short do.bat file. It shouldn't be
too hard to modify this batch file to do what you want.

--
Make that pile of digital photos presentable: http://ourdoings.com/
It's quicker and easier than you think.
 
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Aerticus
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      11-12-2004, 04:59 PM
The moral of the story is:

1 - DON'T EDIT ORIGINAL IMAGES (leave original prime date prime and
unmodified)

2 - only edit or work on copies of the originals (preferably after entring
IPTC data)

3 - store data of prime digital images away from and separate to work in
progress edited copies

4 - well, all above IMHO

Aerticus

"Bruce Lewis" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> JHoffnagle <(E-Mail Removed)> writes:
>
>> I'd also recommend updating/replacing any application that trashes the
>> EXIF data fields - in the long run you won't regret it.

>
> I think Huffy is right on with that comment.
>
> However, if you have some application that you can't update or still
> trashes EXIF information, another step you can take is to rename the
> files with the date/time they were taken. This can be done in a batch
> with the free jhead program. You can also rotate according to your
> orientation sensor with jhead if you've also installed jpegtran.
>
> Download an example of jhead/jpegtran usage from here:
>
> http://img.ourdoings.com/windows.html
>
> (I got the impression you were on Windows. If you're on Linux there's a
> link from there to the Linux version.)
>
> After you download it, look at the short do.bat file. It shouldn't be
> too hard to modify this batch file to do what you want.
>
> --
> Make that pile of digital photos presentable: http://ourdoings.com/
> It's quicker and easier than you think.



 
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David Dyer-Bennet
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      11-12-2004, 07:00 PM
Terry Pinnell <(E-Mail Removed)> writes:

> I suspect I'm being unduly optimistic in hoping this is a question
> with a relatively simple answer!


Yes, in my experience that's correct :-(.

> When I browse folders of old photos, I would often like to know the
> precise date and time they were taken. But the EXIF data is missing
> for many. Presumably EXIF info must have existed for *all* of them
> when I first downloaded the DSC000xxxx.jpg images from my Sony
> Cybershot DSC-1 to my PC, but editing has destroyed it?


Most likely. I mean, you *could* have run a specific program to
remove it, but you'd probably remember doing that :-).

> Does anyone have or know of an up to date list of all operations by
> specific graphic editing programs which result in such destruction of
> the EXIF data please, so that I can make a point of avoiding them?


No. (Since you carefully asked for a list that's both *complete* and
*current*, no, nobody has it. But if I'm wrong and you get it,
forward a copy to me too please?)

> Am I right that although Operation X in Program A might preserve EXIF,
> Operation X in Program B, or Operation Y in Program A (etc) might
> destroy it? IOW, it's something of a mess? If so, I guess the safest
> bet is to keep a copy of those originals, or at least a compact list
> of some sort of their EXIF dates, for future reference if it's
> inadvertently lost?


So far as I've found, it's at the program level, not the operation
level. Although possibly (haven't found an example yet) save
vs. save-as might give different results.

I *did* just discover that when Irfanview writes IPTC data (not quite
the same issue) it appears to delete one field (sub-location) if it's
present. Bummer. But that's the only single-field example of damage
to data embedded in image files that I've found. So far.
--
David Dyer-Bennet, <mailto:dd-(E-Mail Removed)>, <http://www.dd-b.net/dd-b/>
RKBA: <http://noguns-nomoney.com/> <http://www.dd-b.net/carry/>
Pics: <http://dd-b.lighthunters.net/> <http://www.dd-b.net/dd-b/SnapshotAlbum/>
Dragaera/Steven Brust: <http://dragaera.info/>
 
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Alan Meyer
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      11-12-2004, 11:33 PM
"Terry Pinnell" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> ...
> Does anyone have or know of an up to date list of all operations by
> specific graphic editing programs which result in such destruction of
> the EXIF data please, so that I can make a point of avoiding them?
> ...

I don't have a list, but I can recommend a kind of solution.

The free image viewer IrfanView can write out the EXIF data to
a file. It can even do it in batch mode. If you're able to do simple
programming in a scripting language it would be very easy to set
it up to do something like:

For all files in a directory:
Extract the EXIF data to a file with the same base name + ".txt"

You could run this each time you download images from your camera.
Then no matter what your image editor did to the images, you would
at least have the text of the original handy.

But of course you probably still want to save the original images too.

Alan


 
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Terry Pinnell
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      11-14-2004, 05:26 PM
Many thanks for all those helpful replies. Following up several of the
suggested software packages. Looks like I *was* optimistic in looking
for a no-brainer solution then!

--
Terry, West Sussex, UK

 
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