Before the holidays I started to use Apple's Aperture photo management software. Mainly because my new camera lets me shoot in Raw, and I also wanted more control over editing and organizing all my photos. The following bugged me for awhile, so I am posting it here as a reminder to myself:
How to bulk remove keywords in Aperture
If you import your library from iPhoto, there is a new keyword on every single photo called 'iPhoto Edited'. Removing this keyword is simple once you know how.
Click on 'Projects' Tab.
Click on 'All Photos'
Under View menu choose 'Browser Only'
Select All the photos - Command A.
Press 'Shift D' to show keyword controls
In the 'Add Keyword' field, enter the keyword you wish to remove
Then press 'Shift Return'
All of the photos you selected will have that keyword removed automatically.