Exporting photos into a new
Catalog
Whilst it's possible to export photos into a new catalog
from any one of the five Lightroom modules it is much easier if done from
the Library modules Grid view. So, the first step would be
to switch to the Library module, as shown in figure 1.

Figure 1 - Lightroom Library Module (click image for larger view)
Next, we identify the folder or folders containing the
photos that we want to export into the new catalog. In the example shown
in figure 2 we have chosen a single folder named Edited DNG Backups,
but it could equally have been two or more folders. When exporting an
entire folder, it isn't necessary to select the actual photos, just the
containing folder. That being said, it is sometimes desirable to export a
small selection of photos from one or more folders. Fortunately,
Lightroom is flexible enough to allow both.
Update - 8 June 2010: Lightroom 3 has just shipped
and many readers are asking if this tutorial still applies. The answer
is - yes. The few changes that have gone into the Library module
shouldn't change the method described.
Tip: to select multiple folders - we click on
the first folder then, while holding down the Cmd (Mac) / Ctrl
(Windows), click on the other folders that we want to be included
within the new catalog.

Figure 2 - Selecting a folder
Having selected the folder(s) that we want to
export
to a new catalog we choose the Export as Catalog command from the
File menu (figure 3). The Export as Catalog dialog will open. Note
that there is no keyboard shortcut for this particular command, however,
it is possible to create one or remap an existing shortcut using the
method described in this linked
tutorial.

Figure 3 - Choosing the Export as Catalog... command
Our next step is to give the new catalog a name and
define the content. But before doing so it's worth describing what each
of the three options in the Export as Catalog dialog (figure 4) does.
Export selected photos only
When this option is checked only the photos that have
been selected in Grid view will be exported to the new catalog. However,
be aware that this option simply exports the metadata (e.g. IPTC, EXIF,
keywords and any develop settings) associated with each photo into the
new catalog, the actual files (negatives) will not be included. In some
instances this may be all we require, but in others it may be important
that the actual files are also included. We'll address this latter situation in
a moment. Typically, this option is only used when we wish to export a
small subset of photos from a folder or multiple folders. Leaving it
unchecked is important if we want the new catalog to include all photos
within the selected folder(s).
Export negative files
With this option checked Lightroom will export a copy of
each raw file into the new catalog. If the photos include Virtual Copies
and/or sidecars these too will be included in the export. Likewise, any
PSD, TIF or JPEG files that are contained within the selected folder(s)
will also be exported. This option is generally used when the new catalog
is to be transferred to a new computer, stored on an external or disk or
DVD, or shared with a third party.
Include available previews
With this option checked Lightroom will include all
available previews for each of the photos included within the export.
Typically, these will include the thumbnails, standard-sized and, when
available, full-sized previews. If this option is left unchecked
Lightroom will need to render the previews when the new catalog is first
opened. For this reason, it is very important that this option is checked
in situations were the negative files are not exported to the new
catalog.

Figure 4 - Defining Catalog content
The example shown in figure 4 above is ideal for
situations when we simply want to create a smaller catalog that's to be
stored on the same computer as the original and points to the original
photos. A good example of this would be were a user has a master catalog
containing all of their photos and smaller catalogs dedicated to
individual years or themes. On the other hand, there may be situations
when we simply need to export only the metadata associated with a
particular set of photos (e.g. to facilitate syncing of metadata between
catalogs). In which case all three options should be left unchecked.

Figure 5 - Mac OS folder view of new Catalog
Figure 5 shows the Mac OS folder view of the exported
catalog described above. Notice that it it contains only two files (i.e.
the lrdata preview file and the lrcat catalog
file). Had we also checked the second option (i.e. Export negative files)
then a folder containing the negatives would also have be included.