DNG and XMP

Forum|Forum|3 years ago
February 7, 2023
3 replies
4966 views

I just want to understand this — I have enabled the option "Automatically write changes into XMP" in Catalogue Settings, but there are no sidecars, because, as I understand metadata is embeded into DNGs? So, then what this option does in my case? What is the difference if it's checked or unchecked when there are no XMP files anyway?

macOS

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dj_paige

Legend

I have enabled the option "Automatically write changes into XMP" ... What is the difference if it's checked or unchecked when there are no XMP files anyway?

If you check the option, your metadata and edits are written into the DNG file. I you don't check the option, then nothing is written into the DNG file.

DdeGannes

Community Expert

Additional info also available at the link below.

https://helpx.adobe.com/lightroom-classic/help/metadata-basics-actions.html

Regards, Denis: iMac 27” mid-2015, macOS 11.7.10 Big Sur; 2TB SSD, 24 GB Ram, GPU 2 GB; LrC 12.5,; Lr 6.5, PS 24.7,; ACR 15.5,; (also Laptop Win 11, ver 24H2, LrC 15.0.1, PS 27.0; ) Camera Oly OM-D E-M1.

Conrad_C

Community Expert

The metadata is written to external XMP files when the format is either read-only (like camera raw) or doesn’t support it.

When the format does allows writing metadata to the file, then the command updates the file. So if you use that command when a DNG (or JPEG, TIFF, etc.) file is selected, the metadata portion of the file is updated, which doesn’t affect the image data.

R

richardplondon

Community Expert

When it's all happening in the same file, your operating system will keep reporting that whole thing as newly changed, just because you moved a slider or two. Something to consider.

I haven't seen any complaints of file corruption to DNGs from repeatedly writing XMP into those - the file format is designed for that - but my personal judgement is that a separation of completely unchanging proprietary Raw vs changing LrC metadata file makes sense.

XMP sidecars are certainly the more efficient to re-backup regularly. And if simply discarded, you are then left with an untouched Raw that's still exactly as the camera made it. The only exception I know of, is: if correcting capture date and time, that change can get written out into the proprietary Raw as well as into XMP sidecar, if you check a setting in preferences to permit LrC to do so.

Conrad_C

Community Expert

But how do I choose to write in a separate XMP file? I already have that option selected, yet, I don't have any sidecar files next to my DNGs.

But how do I choose to write in a separate XMP file? I already have that option selected, yet, I don't have any sidecar files next to my DNGs.
By @hamadahiro

It’s not written as clearly as it might be, but a big clue is that the word “sidecar” never appears in that Metadata settings window. It says XMP and it’s writing XMP, so it does what it says…but for formats that allow writing into the file itself, the XMP metadata goes into the file.

Not saying there’s anything wrong to want a sidecar even for formats that can write internally, it’s a perfectly legitimate request. But for now, that option isn’t provided, and adding that capability is apparently not high enough on the list of feature requests Adobe decides to work on next.

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