Author Topic: Question about unwanted xmp files, jpegs, and nefs  (Read 1381 times)

rgdudley

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Question about unwanted xmp files, jpegs, and nefs
« on: July 20, 2014, 04:26:52 PM »
I have a database of about 24k images and have used iMatch for quite a few years gradually learning along the way... and of course best practices have changed with regard to xmp files.   

1.   Because of its history my images have quite a few xmp files associated with them, but I am rather sure that I do not need these as I have selected the options to have iMatch create and use imbedded data.   And I have checked that on a few folders by deleting the xmp files in that folder and seeing that the data still appears correctly in iMatch.   Also, when I edit metadata for a jpeg image no new xmp file is created, but the new information is correctly stored during write-back for that image.   

Question: Can I delete all the xmp files in my image folders?


2.   I do not use NEF files very often, but for special circumstances I do.   I have tried to select the options that allow iMatch to write metadata onto the NEF image files rather than use xmp files.   Nevertheless, if I edit the metadata for an NEF image and do the write-back, then iMatch creates a xmp file associated with that NEF.   I notice that iMatch soon writes that new data to the NEF image file (I can check by renaming or deleting the xmp file).   But iMatch does not seem to delete the associated xmp file.   

Question:  Do I need these xmp files associated with the NEF metadata?    Is there a setting that prevents their creation?

Thanks, Richard
Etna, New York, USA
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jch2103

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Re: Question about unwanted xmp files, jpegs, and nefs
« Reply #1 on: July 20, 2014, 05:18:52 PM »
There have been several discussions lately on the forum about xmp files, e.g.,
https://www.photools.com/community/index.php?topic=2903.msg18818#msg18818 and
https://www.photools.com/community/index.php?topic=2753.msg17866#msg17866 and
https://www.photools.com/community/index.php?topic=2793.msg18599#msg18599

Keep in mind that one of the benefits of IMatch is that it transparently handles xmp files; while you're in IMatch you don't have to worry about seeing or handling them. And they're typically very small, only a fraction the size of image files so their impact on storage space is very limited.

The default for jpg files is to embed metadata in the image file, not in xmp sidecar files. So, in theory, they should be extraneous. But I assume you'd want to ensure they aren't actually necessary.

The default for nef and other raw files is to use xmp sidecar files. That's what Adobe and other applications do. But IMatch is flexible enough for those who still want to embed metadata in the raw image files (see the Metadata and Metadata 2 settings). But there are reasons the defaults are set up the way they are.

John
Albany NY
John

cytochrome

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Re: Question about unwanted xmp files, jpegs, and nefs
« Reply #2 on: July 20, 2014, 06:34:39 PM »
Hello Richard,

You don't need xmp sidecars with jPGs , and you should not use them, JPG is a perfect container for xmp.

Concerning NEF, you should follow John's advice, IMatch is really geared toward using xmp sidecars with Raw and if you use Adobe programs it is definitely the way to go, they will anyway write sidecars and your metadata will be out of synchrony between sidecar and Nef unless you are very careful and organized.

This said it is perfectly possible to use NEF, Imatch and no xmp sidecars. I do it and it works fine. But I don't  use LR, PS etc... What I do:

- in Preferences/Metadata2 keep everything by default apart from XMP Export/Allow to write XMP files  that I set to NO
- in the same panel in Configure Fule Formats, for NEF I have "XMP sidecar Files" set to "Embed XMP in File"
- I also have Write IPTC, Exif and Allow create IPTC/Exif/GPS all set to yes, but this really depends on how you want to handle your metedata.

If you want to try, do it on a test folder until you are convinced it works like you want. A good way to verify what is written or erased from the NEF is to use ExiftoolGUI.

I do without sidecars for "historical" reasons, always used programs like IM3 that allowed writing metadata to the NEF, so I have tens of thousands of these with embedded xmp. If I used LR like many here I would have exported my metadata from the NEF to sidecars...

Francis

Mario

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Re: Question about unwanted xmp files, jpegs, and nefs
« Reply #3 on: July 28, 2014, 08:09:19 PM »
See also the changes made in 5.1.12 regarding XMP files:

https://www.photools.com/community/index.php?topic=2974.msg19344#msg19344