XMP Explained!

In Photo Taco Podcast by Jeff Harmon4 Comments

Jeff walks through the details of XMP, what it is, why photographers should care, the pros and cons, multiple options to turn in on in Lightroom, and a couple of lesser known options.

Episode Resources

Introduction

Hey everybody, welcome to another episode of Photo Taco on the Master Photography Podcast Network. I am your host, Jeff Harmon, thanks so much for spending a few minutes of your day with me.  If you haven’t already subscribed to the Photo Taco feed, unless you are driving, pause the show right now and go do that. Yes, you on that exercise bike in the gym, you need to pause right now and go subscribe to the Photo Taco podcast.  

Photo Taco Subscription Contest

To add a little incentive to subscribe to the Photo Taco feed I am running a contest.  The prize is a 30 minute Skype session with me where I will post-process as many photos from the winner as we can get through in those 30 minutes.  If you have taken video training courses and found value in them, imagine how much MORE valuable 30 minutes of training on your photos will be! You will see every move I make on your photos in Lightroom and Photoshop and even more important I will talk you through why it is I am changing sliders, adding adjustment brushes and filters, and what it is I am doing in Photoshop.  

To enter the contest you have to subscribe to the Photo Taco podcast on your podcatcher of choice, take a screenshot on your phone of your podcatcher showing you are subscribed, and send that screenshot as an email to phototacopodcast@gmail.com.  You can enter starting May 14th 2018 and the contest will goes through 11pm mountain on July 6th, 2018.  Only one entry subscription to the podcast, so please don’t send me your screenshot more than once or I will have to disqualify you.  You can get two more entries, for a total of 3, if you get a friend to subscribe to the show and they mention you in their email showing they subscribed.  The winner will be announced on the July 9th Photo Taco episode. Don’t worry if you are driving and couldn’t write any of that down, you can find the instructions on how to enter at the new home of the podcast over at https://phototacopodcast.com/contest.

What Is XMP?

Now let’s get to the topic of this episode, XMP.  Let’s start at the beginning with what is XMP is. Like so many things in technology, XMP is an acronym that stands for Extensible Metadata Platform.  For some of you listening this may be your first introduction to XMP sidecar files, but XMP files are far from new. XMP was initially created by Adobe back in 2001 as part of the Adobe Acrobat 5.0 software product.  

The intention and hope was to have the world use XMP as a standard way for different companies creating software to easily share something called metadata information in a consistent way.  They tried to release XMP as an open source standard, but they did it under something called the Adobe open source license, which isn’t the same as what most open source software is licensed under, GNU General Public license.  This hurt adoption of XMP as a standard until 2012 when Adobe worked with partners to have XMP become an international standard, ISO 16684-1. This put other companies at ease and today there are over 20 international partners who support and very actively use XMP in their software essentially the same way that Adobe does in Lightroom.  I will put a link on the show notes to Adobe’s XMP page if you are interested in reading about that.

What Is Metadata?

So this metadata, why do we as photographers care what it is and why would Adobe work so hard to make it as easy as possible to share it with other software.  Metadata is a fancy word often used in technology for when there is additional information about the creation or production of something digital. Some of examples of metadata are the date and time a digital file is created.  The last date that file was opened or edited. The full name of the author who created a file. Those are all things you are probably used to seeing for not only photos but also written documents and other types of digital files.  Metadata describes or provide details about the data in the file without being part of the actual data contained within the file.

Metadata and Photos

All of the photos you take have metadata put into the file by your camera.  The date/time that the photo was taken, the dimensions of the photo (how many pixels high and wide), the Camera maker, the Camera model, the shutter speed, aperture, and ISO settings.  That is all metadata your camera puts inside the digital file as it writes that data out to the memory card. You have seen metadata for your photos all the time when you click on one in Finder on the Mac or Windows Explorer on Windows.  

Metadata has been such a big part of the digital world all along that most file formats define a specific place where it is to be stored so that it can be shown easily in Finder or Explorer.  However, in the case of Raw files, each camera maker has really decided not to play nice with other camera makers and each has a different way to store all of the information including the metadata.   If you shoot JPEG then a lot of that metadata is stored in the file as dictated by the JPEG standard which defines everyone has to put it in the file the same way.

Metadata and Lightroom

Let’s put it in terms of Lightroom to make it easier.  In multiple Photo Taco episodes I have talked about the Lightroom Catalog.  It is a database where Lightroom records every step you make as you process your photos in Lightroom.  You can also use Lightroom to add more metadata bout your photos. Lightroom reads in all of that metadata information your camera puts in the photo file but you can use Lightroom to add more metadata like ratings, keywords, GPS location information, and face detection that all ends up getting stored in the catalog.  By default, Lightroom is configured to have that be the only place this data is available. You will have noticed this if you have every edited a photo in Lightroom, closed it and then same JPEG or Raw file in another editor Bridge, Photoshop, Paint Shop Pro, GiMP, whatever, that editor knows nothing about the edits you have made to the photo.  Lightroom only recorded the post-processing you did inside the catalog.

XMP – Mini Catalogs

XMP files are kind of like little mini catalogs that other programs can recognize.  Most of the changes you make in Lightroom end up there, outside of the catalog that only Lightroom has access to, making those changes available to programs other than Lightroom.  In fact, it is the only truly supported way to have the changes you make in Lightroom get out to any other program. Many file types, like JPEG, TIFF, PSD, and DNG define as part of the file format a place where Lightroom can put this metadata so it doesn’t have to write out a second file next to them.  In the case of raw files Lightroom creates a second, very small file named the same as the filename of the photo with a .xmp extension because writing back to the raw file can cause issues with other software reading them. Plus, while you might be sad if you lose your edits to a photos, think of how sad you are going to be if something bad happened while Lightroom was trying to update the metadata inside your Raw file and it corrupted the entire file so that you lose the original photo.  The chances of having that happen increase as the size of the file increases and Raw are bigger than JPEG so I think it is a very wise decision to just write a little sidecar file next to the photo.

Why Not XMP By Default?

It all sounds pretty good at this point doesn’t it?  Yet Adobe has decided that writing XMP data outside of the catalog is disabled by default, meaning you have to turn it on yourself if you want it.  Why would we all want to have XMP files written next to our photos? Isn’t this a really good way to backup the edits you are making in Lightroom? I am going to address that question right after thanking the sponsor for this episode:

XMP sounds awesome right now doesn’t it?  Are there down sides? Why would Adobe have the default configuration to have this turned off?  While I am not all confident Adobe is always making decisions based on what is best for the customer, I don’t think this is a case where they are doing this just to try and keep photographers from using other products.  It does sort of accomplish that objective where it isn’t super easy to get your edits out of Lightroom and into a competing editor, but I don’t think that is the reason for this default configuration to have XMP files disabled.  Let’s go over the pros and cons of writing XMP files

Pros:

Cons:

  • You increase the chances of corrupting files as metadata is written to them.  This only applies to JPEG, TIFF, PSD, and DNG files (anything but raw) where Lightroom will write this metadata inside the files instead of as a sidecar file.
  • Another one, that again only applies in the case where you don’t have raw files, where any automated backup solution is going to think that it has to backup the entire file again.
  • Limited data.  Due to limits in the XMP format, not EVERYTHING you do in Lightroom ends up in XMP files or the metadata of non-raw files.
  • Performance

How to Enable XMP

There are two ways to have Lightroom write XMP outside of the catalog:

  1. One way, which is something I have been super hypocritical about because I have taught this many times and don’t really do it myself, is to do it manually.  This would completely remove the reason I choose personally to not have XMP turned on with the performance problem. At the end of processing a shoot, before exporting the photos, go to the Library module grid view (the shortcut for that is just hitting the “g” key), select the photos you want to save XMP data for, press ctrl-S on Windows command-S on Mac and then go to the metadata menu and choose Save Metadata to Files.  (unless you are editing a lot of non-raw files and then I would make sure you have those files backed up before you do this)
  2. The second way is to turn on the automated feature so that Lightroom is constantly doing this in the background as you edit your photos.  Again, this is something I personally am choosing to NOT to enable mainly for performance reasons. You will see decreased performance when keywording, in Develop, and overall after first turn it on.  Especially if you have a lot of photos in your catalog you have now asked Lightroom to go through every one of them and write XMP data out to the disk. You don’t want to go back and forth on this. Even if you may have at one point in the past had this turned on, Lightroom is going to go through all of your photos every time it is turned on even if you did it in the past.  Turn it on and leave it on, or leave it off. To turn it on, you go to Lightroom->Catalog Settings on Mac and Edit->Catalog Settings on Windows, then go to the Metadata tab and choose “Automatically write changes into XMP”.

Lesser-Known XMP Options

While you are there you may have noticed there is an additional checkbox at the bottom of that same panel that says “Write date or time changes into proprietary raw files.”  This is the one exception where Lightroom will write a metadata change directly to a raw file. If you edit the capture time in Lightroom and you have that checkbox checked, then the capture time of the raw file will be changed.

You may have also noticed in that same Metadata panel a checkbox labeled “Include Develop settings in metadata inside JPEG, TIFF, PNG, PSD files”.  By default it is checked, but if you are like me, and having Lightroom touch those files scares you to death – you just want Lightroom to leave them alone, then unchecking the box will tell Lightroom to write sidecar XMP files for all of those file types in addition to raw.

Contact the Show

All right, that is all the time we have for this episode.  I hope you all enjoyed it. You can now find everything Photo Taco related at the new home for the podcast over at phototacopodcast.com.  Searchable show notes are there, a link to the Photo Taco Listeners Facebook group, and a few other goodies I am working on that are only available to visitors of the website.  I would love to connect with you through Instagram where the show’s account is @phototacopodcast, on Twitter where the show is @PhotoTaco, or you can drop me an email at phototacopodcast@gmail.com.  No question is too basic or to complicated for the show.  If I don’t know the answer to the question, I’ll see about bringing an expert guest, on the show to go through it.  Photo Taco is part of the Master Photography Podcast Network and you can find everything about the network at masterphotographypodcast.com.  Together we want to help you master your photography!

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Comments

  1. Great podcast Jeff! Coming into the podcast I really had no real understanding of XMP . . . and now I know. I’m changing my LR catalog to make use of XMP . . . but doing so knowing the pros/cons of doing it. Thank you.

    1. Author

      @Ken, so glad to hear you found it beneficial. Everyone should have the information they need to make a decision for themselves how they want to configure and use Lightroom. Best of luck with you XMP!

  2. Great info Jeff. I didn’t fully appreciate the value of xmp until your podcast. I also like your LR tips. Question, have your done a top ten LR setup tips podcast yet? Some the tips in this podcast made me wonder if you had. Didn’t see any when I searched. Thanks.

    1. Author

      @Dudley

      I don’t think I have done a Top Ten getting started with Lightroom tips episode. Good suggestion, I will add it to my very lengthy list of show ideas :).

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