Apple Aperture 2 - Manual (Page 288)

288 Part II Photo Editing
Batch Changing Metadata
You can select a group of images and make metadata changes to all the images at
once. For example, if you need to add the same set of keywords to a selection of
images, or change the version name format, you can select the images and use the
Batch Change dialog to change them.
To change the metadata associated with a selection of images:
1 Select the images you want to change.
2 Choose Metadata > Batch Change (or press Command-Shift-B).
3 In the Batch Change dialog, choose a metadata preset from the Add Metadata From
pop-up menu to select a preset template of metadata to be applied.
You can select the Append button to add the metadata to that already applied to the
selected images, or select the Replace button to add the metadata and replace any
previously assigned metadata.
4 Enter any metadata you want applied in the metadata fields.
5 Specify any other metadata options you want to change, then click OK.