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Fix Photos (different H/V resolution)

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Offline acseven

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Fix Photos (different H/V resolution)
« on: 18 / January / 2009, 07:14:14 »
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Hi,

I have an archive of old photographs (about 5000), taken with a Creative Camera/webcam, that have a problem.

When viewing in explorer or the preview app of XP/Vista, the picture doesn't display correctly. If I open it with Lightroom, for example it opens just fine.

The problem is that (and sorry for the english terminology, don't know if it's correct) the vertical resolution is correctly set to 72 dpi but the horizontal is set to 1 dpi, instead of 72 dpi. This makes the image appear like a very slim bar!!

How can I batch correct this? I am able to select all the photos by camera in lightroom for example.
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Offline barret

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Re: Fix Photos (different H/V resolution)
« Reply #1 on: 18 / January / 2009, 07:46:55 »
the fastest way to fix this is removing exif data, but i'm not sure if this suits your needs.
anyway, if you want to loose exif data, all you have to do is batch process your photos in irfan view, save files as jpg, and disable "keep original EXIF data" option. This way you will loose ALL exif data, including dpi setting (which you will probably don't need anyway).

also, i think GIMP have some advanced batch processing functions.

greets
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Offline fudgey

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Re: Fix Photos (different H/V resolution)
« Reply #2 on: 18 / January / 2009, 07:56:19 »
Is DPI really in EXIF?

Irfanview may be able to batch process this losslessly. I don't run windows so I'm not sure.

Imagemagick (using -density 72x72) does this and can of course be easily scripted to work in batch, but on a quick try it recompressed my jpeg, which is a no-no quality-wise.
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Offline fe50

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Re: Fix Photos (different H/V resolution)
« Reply #3 on: 18 / January / 2009, 08:27:35 »
You can try XNView (free for private use).

Select the thumbnails in the browser tab, call 'Tools' - 'Batch processing' from the menu,
set up the things on the 'General' tab (select a new folder for the converted files, adjust the destination format etc.),
then go to the 'Transformations' tab, add 'Set dpi' from 'Image'...
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Offline acseven

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Re: Fix Photos (different H/V resolution)
« Reply #4 on: 18 / January / 2009, 08:59:54 »
Thanks for the reply.

I think it is in the EXIF data, because it happens only with photos from this camera, but I actually can't see this when viewing the EXIF data in Adobe Lightroom.

I guess that XNView and irfanview could do it, but there's one small problem... I'm talking about 5000 photos, spread about lots of folders...!

In Lightroom is very easy to select all of them, by EXIF filters, so that's why it'd be great to do the correction there.

Ayyway, thanks for the suggestions, I'll give them a try.

Cheers

ps: posted an example (it appears correctly here)

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Offline fe50

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Re: Fix Photos (different H/V resolution)
« Reply #5 on: 18 / January / 2009, 11:00:56 »
XNView can do it all easily for you...but the images will be changed  ;)

Test: Open such a pic in XNView & press ALT-Enter: the EXIF data seems to be correct (72x72), but in the image there's 'Pixel per inch: '? ? ? x ? ? ?'; after using XNView's 'set dpi' command this is fixed.

So let XNView run through all your sub folders & let it store the corrected images in a new folder with exactly the same folder structure...

-> All the pic must be in a folder, no matter how much pics / sub folders you have there
-> Start XNView, call 'Batch processing' (CTRL-U), 'Remove all' to remove selected folders, then press 'Add folder'
-> All images (also in the sub folders) are listet
-> set 'Output directory' to a new, empty dir
-> check 'Keep subfolder structure', 'Keep original date/time...', 'Keep source format'
-> Adjust 'Format Options' to the settings you want (e.g. JPEG format: keep EXIF data, Quality)
-> set up the transformations you want (in the 'Transformations' tab): Set DPI -> 72 x 72

You can also save the settings as a script file for later usage...

It'll run some time... then you should have the whole folder structure with all the fixed images...

Remember: the images will be recalculated, so the image quality could be changed, backup your original files / work with a copy !
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Offline acseven

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Re: Fix Photos (different H/V resolution)
« Reply #6 on: 18 / January / 2009, 12:33:12 »
Thanks very much for that walktrough. I actually installed xnView and started the process, but I ended going back to Lightroom (stubborn me), mainly because I couldn't easily select all the photos. I have tons of photos from other cameras in the subfolders, and it didn't want to change anything on those.

So... LR should be able to do anything with a photo, and some more, and it does! I followed your logic and got to a somewhat similar process of exporting photos with changing only the DPI, and was successful.

The main advantage of LR here was the fact that I could filter the photos based on metadata!

Thanks very much for your pointers ;)
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