Making Sense of Metadata Settings in Lightroom

• By Martin Evening
• May 16, 2008
• Article is provided courtesy of Peachpit Press

From the author of
Adobe Photoshop Lightroom Book, The: The Complete Guide for Photographers

As you enter metadata for keywords and other editable metadata fields, you can save time by having the "Offer suggestions from recently entered values" option checked in the metadata catalog settings (see Figure 1). This option was selected by default in Lightroom 1.0, but now you can choose whether to keep it switched on, and you can click the Clear All Suggestion Lists button to reset the memory to clear all memorized words.

Figure 1 Metadata catalog settings.

Most of the time, auto-completion can be useful to have active, but sometimes when entering certain metadata the auto tool can become a pain. For example, when I do a model casting and enter the names of models in the Title field of the Metadata panel in the Library module, I don’t find auto-completion particularly helpful. Every model’s name is different, and sometimes it’s easier to switch off this feature rather than fight with the suggestions that Lightroom is making on my behalf.

The option "Write develop settings to XMP for JPG, TIFF, and PSD" is new. It provides the ability to distinguish between writing the develop settings metadata to the XMP space for all files including JPEGs, TIFFs, and PSDs; or to raw files and DNG files only. This preference predetermines what gets written to the XMP space when you make an explicit command to save the file metadata out to a file, such as when:

• In the Library module, you select Metadata > Save Metadata to File.
• In the Develop module, you choose Photo > Save Metadata to File.
• You press Command-S (Mac) or Ctrl-S (PC).
• The "Automatically write changes into XMP" option is switched on in the Catalog Settings dialog box.

Let’s take a closer look at what this XMP setting business is all about. The XMP space is the hidden space in a document—such as a JPEG, TIFF, PSD, or DNG file—where Lightroom writes the metadata settings. In the case of proprietary raw files, it would be unsafe for Lightroom to write to the internal file header, so .xmp sidecar files are used to store the XMP metadata. The XMP metadata consists of everything that’s applied in Lightroom, including the following:

• Editable metadata data such as the IPTC information applied via a metadata template
• Keywords
• File rating flags
• Color labels
• Develop settings that are applied via Quick Develop and the Develop module

The ability to save develop settings with the file can be a mixed blessing. If you’re sharing images exported from Lightroom as individual images or as an exported catalog with another Lightroom user, you’ll definitely want to share the develop settings for all the images contained in the catalog. But if you’re sharing files from Lightroom with Bridge 2 as part of the Adobe Creative Suite 3, sharing develop settings can lead to some unexpected file behavior when you open non-raw files via Bridge 2. Basically, what will happen is that raw and DNG images that have had their develop settings modified via Lightroom will open via Camera Raw in Bridge exactly as you expect to see them, since Bridge 2 is able to read the settings that were created in Lightroom. However, where you have edited a non-raw file such as a JPEG, TIFF, or PSD image using the develop settings in Lightroom, and the develop settings have been written to the file’s XMP space, Bridge 2 will consider such files to be raw files and will open them via Camera Raw rather than directly in Photoshop. That’s what I mean by mixed blessings. If you want Lightroom to retain the ability to modify the XMP space of non-raw files for data such as file ratings, keywords, labels, etc. but exclude storing the develop settings, uncheck the "Write develop settings to XMP for JPG, TIFF, and PSD" option. If you do this, your Lightroom develop settings for non-raw files will only be written to the catalog; they won’t be exported when you choose Save Metadata. But raw and DNG files will continue to be modified as before. On the plus side, you’ll never be faced with the confusion of seeing your non-raw images (such as JPEGs) unexpectedly default to open via Camera Raw when you try to open them in Photoshop CS3. The downside is that if you modify a non-raw image in Lightroom using the develop settings, these changes will be seen only in Lightroom, not in Bridge.

The "Automatically write changes into XMP" option is normally unchecked. At first, it would seem like a good thing to have this option switched on all the time, so that Lightroom continually updates the XMP metadata as changes are made via the program. Unfortunately, doing so can really slow Lightroom’s performance. For this reason alone, it’s better to have this option switched off. When this option is disabled, all Lightroom metadata edits are stored in the internal catalog file only. If you intend to export images from Lightroom either singly or as an exported catalog, you can simply use the Save Metadata command, Command-S (Mac) or Ctrl-S (PC), to write the metadata directly to the selected files.

Summary of Metadata-Saving Behavior

To help explain the settings and how they affect image files after being modified in Lightroom and then viewed in another program, the following sections summarize how these options affect the way in which the various file formats will be handled. The tables in each section assume that you’re using Photoshop CS3 and have updated Camera Raw to the latest 4.1 version.

Scenario 1

If a photo in Lightroom is modified using the settings shown here, with "Automatically write changes into XMP" and "Write develop settings to XMP for JPG, TIFF, and PSD" switched on, all adjustments made to a photo in Lightroom will be saved automatically to the Lightroom catalog and also saved back to the original image file. In the case of proprietary raw files, the XMP metadata will be written to an XMP sidecar file. As you would expect, when opened via Bridge 2, the files will open via the Camera Raw dialog with the same develop settings that were applied in Lightroom. In the case of DNG files, the XMP metadata will be written internally to the file, and these also will open in Camera Raw.

In the case of JPEG, TIFF, and PSD files, the XMP data will be saved inside the file header itself. However, because you’re also saving the Lightroom develop settings, these files will default to opening in Bridge 2 (as part of the Creative Suite 3), always using the Adobe Camera Raw dialog.

Scenario 2

If the "Automatically write changes into XMP" option is disabled, the same rules will apply as before, except that now the metadata edits will be saved to the Lightroom catalog only. If you want the metadata edits to be saved to the file’s XMP metadata space, you have the option to do so manually by using the Save Metadata command. In this example, the "Write develop settings to XMP for JPG, TIFF, and PSD" option is switched on, so you’ll also be saving the Lightroom develop settings to the file’s metadata space.

If you were to open a JPEG, TIFF, or PSD image that had been edited in Lightroom without using the Save Metadata command, the file will open from Bridge 2 directly into Photoshop, not via the Camera Raw dialog. Image ratings, metadata keywords, and any other information that had been entered in Lightroom won’t be visible in Bridge 2 (or any other program outside of Lightroom). If you were to use the Save Metadata command before inspecting these photos in Bridge, all the metadata will be saved to the XMP space, and we’re back to the scenario 1, in which the non-raw files will default to open via Camera Raw—perhaps not what the customer wanted!

Scenario 3

Now let’s look at what happens when the "Write develop settings to XMP for JPEG, TIFF, and PSD" option is disabled.

In this example, if you use the Save Metadata command (or if "Automatically write changes into XMP" is switched on), anything that’s done to edit the metadata of a non-raw photo in Lightroom, except for the develop settings, will be saved to the file’s XMP metadata space. The develop settings will be saved to the Lightroom catalog, of course, but they won’t be written to the file’s XMP space.

In this scenario, JPEG, TIFF, and PSD files that have been edited in Lightroom will open from Bridge 2 directly into Photoshop without going via the Camera Raw dialog. All the other metadata that has been edited in Lightroom will be preserved and remain accessible in other programs—except for the develop settings. Overall, this is a useful configuration for preserving the informational metadata in non-raw files that have been modified via Lightroom. But the develop settings won’t be transferred; hence, the appearance of such images n Lightroom won’t always match how they look in other programs.

Because this setting applies only to non-raw files, all proprietary raw and DNG files that have been edited in Lightroom will preserve their informational metadata and their appearance when viewed in Bridge 2, and will open as expected via the Bridge Camera Raw dialog.