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Keywording in Lightroom

Some precisions on keywording in Lightroom...

As you know, instead of adding tons of keywords to a single endless list and spending a long time trying to find them, a good approach is to create a hierarchy of keywords. You could have a simple tree of keywords such as this one:

Contrary to what you might have been told, when you select a child in a hierarchy, this automatically includes all of its parenthood in the list of keywords attached to the image—not only the child. The confusion comes from the fact that in the Keyword Tags list, the default option ("Enter Keywords") only displays the keywords that were entered/selected explicitly. If you pick the "Will Export" option, on the other hand, you will see the actual list of keywords that will be exported with the image. This reveals that, indeed, the whole hierarchy will be included:

The only exception to this rule is the keywords that have been configured as "Private"—that is to say, that have their "Include on Export" option disabled (such as the root keyword "PLACES" in this example). Notice that, therefore, creating a hierarchy containing variants of a single word (such as plural forms Women/Woman) is not a good strategy, because selecting the child item would automatically include the other version as well.

The same way, you can avoid a lot of redundancy by using a hierarchy. If you were to create a sub-category for "kinds of trees", for example, you wouldn't need to call each tree "Palm Tree", "Oak Tree", "Elm Tree", etc., as the parent is called "Tree", and picking any one of them would already include the parent keyword "Tree".

Once you have keyworded your images, all you need to do to filter the images that were tagged with a specific keyword is to click on the arrow at the right of the keyword (it shows only when you hover the mouse pointer over the area):

As with any other metadata, these settings will be saved in the Lightroom Catalog, but contrary to what you might have been told, they can also be saved into the XMP sidecars or embedded into DNG, PSD or JPG files—the automation of which only depends on the settings of your Lightroom Catalog.

In the "Metadata" tab of the Catalog Settings, if you pick the "Automatically write changes into XMP" option, every time you make a change (be it keywords, develop parameters, crop, whatever), they will be saved into the actual files right away—not strictly kept inside the Lightroom Catalog. This means that even if you were to browse these files from within another compatible application (say, Adobe Bridge), you would indeed see all the metadata.

If you disable the "Automatically write changes into XMP" option, you can still force the settings to be saved to the files, but you have to do it manually. You can have Lightroom display whether the metadata have been saved or not as an icon in the Library Module:

To trigger the update, either click on this icon, or select the files and use the "Control/Command+S" shortcut (this is helpful if you have a bunch of files that need updating).