XMP Metadata Option

[Cleary71]

Hi, I am just beginning to make the transformation to using Lightroom and had an XMP question. I am use to working with Lightroom and having an XMP for each PSD photo I have. One of the things that intrigued me about Lightroom was the ability to make several versions of the same file (color, B&W, cropped, etc.) without having to duplicate the original file 3-4 times. When I went to import a few photos today I noticed that I have the "Automatically Write Changes Into XMP" selected under catalog settings -> Metadata. My question is how does the XMP work with Lightroom. Can I make several versions of the same file and will I get several XMP files or is it just the most recent file I made? I would like to have everything stored on an external drive that is connected to my desktop but do all my processing on my laptop. Would I have to export each file and XMP file when I do this? Any help would be greatly appreciated and I am curious if you think I should have the option on or off.

 

[Gnits]

There is only a single XMP file per parent file. There are no xmp files for virtual files. The contents of the xmp will depend on the setting "Automatically Write Changes Into XMP" and also various options / actions taken within the Lr Gui to update the metadata to disc.

I am critical of Adobe's implementation of their Virtual Copies and metadata. They should either design the XMP file to contain the settings per master and virtual copy or they should have an xmp file per virtual file (if outputting XMP files).

It is dangerous to assume that you can rebuild a catalog file from an external set of data (ie image files and xmp files). There is a lot of information missing, such as collections, but also, you will lose all your virtual images. That is why it is critical to backup your Catalog file onto a different drive than your live catalog or catalogs.

 

[Cleary71]

Thank you. I just had two further questions if you don't mind. I just want to get it correct from the start. So if I did routine backups then the XMP files aren't necessary? If I didn't have XMP files and exported a file to Photoshop from Lightroom would Photoshop be able to see the changes? I would hope since they are both Adobe products, but every time I used Photoshop I have a corresponding XMP file with it due to Camera Raw. Thanks again!

 

[Gnits]

Xmp files take up very little space, so I suggest until you fully understand how you might want to use (or not use) the XMP files that you back them up.

"and exported a file to Photoshop from Lightroom"

You have to be very careful with terminology. Some may use the word Export when they mean "Edit in Photoshop". Are you using the Export function or the Edit in Photoshop option ?

If you import a PSD, apply some changes (eg convert to black and white) and then Export as a PSD, the resultant Psd will be the Black and White Version.

Maybe, if you explained why you wish to use Xmp files we may be able to give you more specific advice.

If you back up your catalog, then all your settings for all files in the Catalog are also backed up.

Third party programs sometimes use XMP files and Adobe will use them for various functions within their apps. For example, some people rate / select images in PhotoMechanic before importing to Lr. PhotoMechanic puts (for example) the star rating info into an xml file, which Lightroom will apply to the image when imported.

 

[Johan Elzenga]

Lightroom does not write XMP files for PSD, and on import it ignores XMP files with PSD. It will write into the PSD metadata. Only RAW files will get XMP files.

 

[clee01l]

Thank you. I just had two further questions if you don't mind. I just want to get it correct from the start. So if I did routine backups then the XMP files aren't necessary? If I didn't have XMP files and exported a file to Photoshop from Lightroom would Photoshop be able to see the changes? I would hope since they are both Adobe products, but every time I used Photoshop I have a corresponding XMP file with it. Thanks again!

XMP files are not necessary for LR. LR communicates to PS in one of two ways. If you have LRCC/PSCC, then LRCC passes the original RAW file and the ACR adjustments to PSCC and PSCC has all it needs to build the edited image via ACR. If you have an older version of PS (CS6), then the ACR adjustments in LR6 are not compatible with the older version of ACR included with PS. Then LR6 creates an intermediate TIFF/PSD with all of the ACR adjustments built in and PS has a derivative image file that it can work with.

There are some instances when LR needs to create a separate XMP side car file. If you are creating HDR or panoramas using the LR6 built-in functions, LR creates an XMP sidecar file for the source files and the HDR/Pano file generated is a DNG file. This does not involve PS.

 

[clee01l]

Lightroom does not write XMP files for PSD, and on import it ignores XMP files with PSD. It will write into the PSD metadata. Only RAW files will get XMP files.

XMP is a section in the header of the image file. It is created in the actual file if the file is of a format that supports it. So JPEGs, PSD, TIFF & DNGs all have an XMP section. Proprietary RAW files can not be expanded to include the XMP section. So, Adobe creates the XMP section is a separate sidecar file.

 

[Cleary71]

Xmp files take up very little space, so I suggest until you fully understand how you might want to use (or not use) the XMP files that you back them up.

"and exported a file to Photoshop from Lightroom"

You have to be very careful with terminology. Some may use the word Export when they mean "Edit in Photoshop". Are you using the Export function or the Edit in Photoshop option ?

If you import a PSD, apply some changes (eg convert to black and white) and then Export as a PSD, the resultant Psd will be the Black and White Version.

Maybe, if you explained why you wish to use Xmp files we may be able to give you more specific advice.

If you back up your catalog, then all your settings for all files in the Catalog are also backed up.

Third party programs sometimes use XMP files and Adobe will use them for various functions within their apps. For example, some people rate / select images in PhotoMechanic before importing to Lr. PhotoMechanic puts (for example) the star rating info into an xml file, which Lightroom will apply to the image when imported.

I wasn't planning on using the XMP files, but when I added GPS to my first imports I noticed them and stopped before I went any further. I just wanted to check with the experts if I needed this or not. I planning on backing up regularly so I suppose I will turn them off. Thanks!

 

[Cleary71]

Lightroom does not write XMP files for PSD, and on import it ignores XMP files with PSD. It will write into the PSD metadata. Only RAW files will get XMP files.

Thank you. I am use to seeing these since I only shoot RAW and then open them in Camera Raw.

 

[Cleary71]

XMP is a section in the header of the image file. It is created in the actual file if the file is of a format that supports it. So JPEGs, PSD, TIFF & DNGs all have an XMP section. Proprietary RAW files can not be expanded to include the XMP section. So, Adobe creates the XMP section is a separate sidecar file.

So if I am shooting RAW and add Metadata LR will add this to a LR specific master file rather than the RAW file itself? Where as the other types it will just imbed the metadata into the image itself?

 

[Gnits]

If you are shooting raw, import the file into Lr and apply settings, then the settings are stored in the catalog. You could opt to have Lr "Automatically Write Changes Into XMP" in which case....Lr can not add these changes to the raw file, but puts the changes in an xml file. [Correction XMP file .... thanks Phil .... I am more familiar with xml generally, so sometimes I use xml in error].

 

[PhilBurton]

If you are shooting raw, import the file into Lr and apply settings, then the settings are stored in the catalog. You could opt to have Lr "Automatically Write Changes Into XMP" in which case....Lr can not add these changes to the raw file, but puts the changes in an xml file.

Minor point here. XMP is the file type. XMP stands for "Extensible Metadata Platform." The format of the XMP file is defined by a technical standard called XML, which stands for "Extensible Markup Language," a geek term if there ever was one.

Phil

 

[clee01l]

So if I am shooting RAW and add Metadata LR will add this to a LR specific master file rather than the RAW file itself? Where as the other types it will just imbed the metadata into the image itself?

LR makes these metadata entries in the LR catalog file. This is the master file that contains everything that you do with images in LR. When you create a derivative image file from the original RAW file, LR will merge the LR develop adjustments into the original RAW data and create a standard EXIF header for the derivative file. This new image file will contain ALL the the metadata changes including an XMP section that describes the Develop adjustments that were applied to the original RAW file.

There is an option in LR to write metadata changes to the original file, but this is an unnecessary redundancy since this metadata is always stored in the LR catalog file. If you choose this option in LR, LR will write the XMP (develop adjustments) metadata to the XMP section along with changes that you have made to the IPTC section etc. If the original is a Proprietary RAW file format, then LR will create a separate sidecar file to contain these data other wise LR writes directly into the header section of non proprietary files like JPEGs, TIFFs or DNGs. Nothing gets embedded into the "image itself" An image file (all files really) consists of two or more parts — a header block (containing the EXIF, IPTC and XMP sections etc.) and a data block containing the data.

Metadata contained in the LR catalog that does not get written to an XMP section/file include things like Collection membership, virtual copies that include an alternate develop history.

 

[Johan Elzenga]

Thank you. I am use to seeing these since I only shoot RAW and then open them in Camera Raw.

OK, fine. You said "I am use to working with Lightroom and having an XMP for each PSD photo I have." A PSD file is a special Photoshop format RGB file, not a raw file.

 

[Cleary71]

OK, fine. You said "I am use to working with Lightroom and having an XMP for each PSD photo I have." A PSD file is a special Photoshop format RGB file, not a raw file.

Sorry about that. I meant Photoshop. I got a little ahead of myself. Thanks again!