WLPG Recovery

[JL]

I'm trying to recover from my photos being exposed to Windows Live Photo Gallery with a variety of unwanted effects, some of which I understand and some of which I don't.

I'm attaching two metadata exports from ExifToolGUI.

"forsyth-a" was altered by WLPG. It was LZW-compressed by WLPG amongst 'other things' and then re-saved, by me, as an uncompressed tif.

"forsyth-b" is a restored file, 3 years old, originally saved as a psd. I re-saved it as an uncompressed tif and then generated the metadata file.

What I'd like to know is if forsyth-a is usable or if the metadata has been altered in unsavory manners that need to be repaired? Or if the photo should be scrapped altogether and I should carry on with forsyth-b? Or, are they close enough to being the same it doesn't matter?

[Phil Harvey]

I'm afraid I don't understand what you want.  Both files contain very usable metadata, although there are certainly some differences.  There appear to be no ExifTool warnings, so structurally the metadata is probably OK.  Content-wise you are the best one to judge if it is suitable for your purposes.

- Phil

[JL]

I know that WLPG made many unsought changes to my photos; GPS (which I've already reversed), compression and metadata.

I have a choice. I can restore the pre-WLPG originals one by one or I can simply re-save the tif's that WLPG compressed with LZW back to uncompressed.

I don't know enough about metadata to know what I need or don't need outside the IPTC and GPS I put there myself. So, that's what I'm asking. Is the example photo affected by WLPG good enough to continue with or is there anything there I should be concerned about?

Or, perhaps more specifically, what are the differences? That might help me to understand what I'm missing if I go with "a" instead of "b".

[Phil Harvey]

I don't have enough information to help you with this.  You say that you lost GPS but there is no GPS in either file you uploaded.  Also, the metadata was entered differently for each of these files.  Presumably the most recent one is the one you should use.

- Phil

[JL]

There was no GPS, until WLPG put it in. I took it back out. So, no, you wouldn't find any there.

The IPTC-annotation has been changed over the past 3 years as you've seen. That's not the part I'm concerned with, at least not in my question to you. When I look at the metadata lists I see different things there. XMP, IPTCext, etc. They're listed differently. There's something called StripOffsets that have different numbers. HistoryParameters. The obscure stuff. At least, obscure to me. If it's been changed from one photo to the other, does any of it matter?

[Phil Harvey]

Generally, the things you didn't enter aren't important.  The StripOffsets just has to do with the structure of the TIFF image.  The History stuff is just something written by Adobe products and I see no practical use for it.  The compression isn't a problem either because LZW is a lossless compression scheme.

- Phil

[JL]

Our mutual acquaintance, Geoff Coupe, (http://gcoupe.wordpress.com/) had a look at the files before, at his suggestion, I posted them here and his question is:

There appears to be a repeated IPTC-IIM block; is this something to worry about?

I'm just trying to cover every base before I launch into this massive restoration. It's a huge relief to find out that LZW is lossless compression and as long as everything else is in order, I will proceed.

[Phil Harvey]

The duplicate IPTC block looks like it may be in a PhotoMechanic trailer, in which case it is nothing to worry about.  But I can't tell for sure with the output you sent.  With the -g5 option I would have a better idea.

But even in the worst case, the only drawback with multiple IPTC data is if you don't keep them syncrhonized.  In this case there may be inconsistency in the IPTC tags reported by different applications.

- Phil

[JL]

-g5?

[Phil Harvey]

-g5?

You attached two output files where you used the -g option.  Try -g5 instead.  (or -v)

- Phil

[JL]

I didn't do that. I exported them as text files from ExifToolGUI.

[JL]

To be clear-er, I don't know how to do it the way you're asking.

[Phil Harvey]

Maybe it would be easiest if you sent me a sample image and I will take a look myself.  My email is philharvey66 at gmail.com

- Phil

[Phil Harvey]

I got the samples, thanks.

Both of the files ("a" and "b") contain IPTC information in the wrong location.  In general, this shouldn't cause problems in other applications if both sets of metadata are kept synchronized (which they are currently).  If you write new tags with ExifTool, the IPTC will stay synchronized, but if you write with other utilities it probably will not, and this is where you could run into problems.

However, deleting the incorrect IPTC is fairly straightforward in this case if you are willing to also delete the Photoshop editing information.  Using -photoshop:all will do this. (The non-standard IPTC is stored inside the Photoshop record.  This is the place it is stored in a JPEG image, but in a TIFF image it is stored in a different location.)

- Phil

[JL]

Thank-you.

"a" is a file altered by Windows Live Photo Gallery, and "b" is the photo restored from backup. I'm only keeping one of them. This same situation would likely apply to thousands of other photos, although I can't say at this point if every single one of them was exposed to Adobe.

I do all my IPTC work using GeoSetter or Photo Mechanic. Although obviously other software was used in the past.

Since I don't use ExifTool directly (I don't know how) can -photoshop:all be used in ExifToolGUI? If not, how do I use it in ExifTool?

[Phil Harvey]

I don't know about ExifToolGUI, but you could post a question in that section of the forum if you don't get an answer here.

With ExifTool, the command is:

exiftool -photoshop:all= -ext tif -ext tiff DIR

where DIR is the name of a directory containing the images (like c:\pictures for example).

Here I have added -ext option to only process files with .TIF and .TIFF extensions.  You could also add a -r option to process TIFF's in subdirectories too.

- Phil