Multiple photo programs - explain sidecars?

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Bbawt1 Forum Member • Posts: 63
Multiple photo programs - explain sidecars?

Think this is a pretty basic question, but I couldn't find the answer anywhere.

I currently use LR CC and want to try out a few other programs. I'm used to the catalog function for storing edits in LR so not too familiar how sidecars work.

Some of the programs I want to test use sidecar xmp files.  What happens when Program A writes the sidecar and then Program B opens the raw file and also writes a sidecar - does it overwrite the existing file? Does a second sidecar get written? I don't want to lose edits from one program by using another program.

Thanks.

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Dan Marchant Veteran Member • Posts: 3,228
Re: Multiple photo programs - explain sidecars?

I don't know. Also different packages may be different so one might overwrite while the other uses a different naming structure.
Why don't you do a test and report back?

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Digital Nigel Veteran Member • Posts: 9,854
Re: Multiple photo programs - explain sidecars?
3

Bbawt1 wrote:

Think this is a pretty basic question, but I couldn't find the answer anywhere.

I currently use LR CC and want to try out a few other programs. I'm used to the catalog function for storing edits in LR so not too familiar how sidecars work.

Some of the programs I want to test use sidecar xmp files. What happens when Program A writes the sidecar and then Program B opens the raw file and also writes a sidecar - does it overwrite the existing file? Does a second sidecar get written? I don't want to lose edits from one program by using another program.

They use different file extensions, so program A's sidecars are stored separately from program B's. They won't overwrite each other, but normally, one program can't read another's sidecars, so you can't transfer edits from one to another.

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myotisone Senior Member • Posts: 1,970
Re: Multiple photo programs - explain sidecars?
4

Bbawt1 wrote:

Some of the programs I want to test use sidecar xmp files.

"XMP" side car files work across programs to share metadata.

Some programs, but possibly only Lightroom writes some processing data to XMP sidecars, which should be LR specific and ignored by other programs.  Unless the other program specifically says that it shares LR processing data.

Other programs such as DXO store processing data in sidecar files, but these are *.dop files not XMP sidecar files. Capture One (C1) stores processing data in *.cop sidecar files.  And these files are only used by DXO and C1 respectively.

However, C1 (and probably DXO) also write "metadata" changes to XMP sidecar files, allowing these changes to be shared across programs.

C1 does not write any processing data to the XMP sidecar files. Nor do they read any of the processing data that LR writes to XMP side car files.  Except, when importing LR catalogues into a C1 catalogue when they try and read the LR processing data as a one one off during import to try and match edits between the two programs.

So, this shouldn't be an issue, but I would still check and see exactly how the programs you are referring to work.

Cheers,

Graham

MisterBG Veteran Member • Posts: 6,863
Re: Multiple photo programs - explain sidecars?
1

myotisone wrote:

Bbawt1 wrote:

Some of the programs I want to test use sidecar xmp files.

"XMP" side car files work across programs to share metadata.

Some programs, but possibly only Lightroom writes some processing data to XMP sidecars, which should be LR specific and ignored by other programs. Unless the other program specifically says that it shares LR processing data.

Other programs such as DXO store processing data in sidecar files, but these are *.dop files not XMP sidecar files. Capture One (C1) stores processing data in *.cop sidecar files. And these files are only used by DXO and C1 respectively.

However, C1 (and probably DXO) also write "metadata" changes to XMP sidecar files, allowing these changes to be shared across programs.

C1 does not write any processing data to the XMP sidecar files. Nor do they read any of the processing data that LR writes to XMP side car files. Except, when importing LR catalogues into a C1 catalogue when they try and read the LR processing data as a one one off during import to try and match edits between the two programs.

So, this shouldn't be an issue, but I would still check and see exactly how the programs you are referring to work.

I think it's true to say that .xmp sidecars contain things like keywords and star ratings that can be read by any program that understands the .xmp protocols.
Other sidecars (.cop, .dop) contain information (usually develop settings) that are known only to the program that wrote them. On1 PhotoRAW also generates it's own (.on1) sidecars containing it's own information.

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Pieloe
Pieloe Forum Member • Posts: 72
Re: Multiple photo programs - explain sidecars?

YES some programs share keywords, GPS tagging and star ratings with .xmp sidecars. Others informations in these xmp files are exclusive to Lr.

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OP Bbawt1 Forum Member • Posts: 63
Re: Multiple photo programs - explain sidecars?

Thanks everyone for your help. Darktable and LR can both write .xmp but each writes their own - so I have 2 .xmp files alongside the .raf raws. Each has their own naming protocol so easy to tell which belongs to which program.  DNGs (which I get using X-Transformer) have the data baked in so no sidecars.  DT, RawTherapp and LR all kept their own develop info straight.  The other commercial software must too.

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