The Adobe Bridge central cache stores thumbnail, preview, and metadata information in a database. This database improves performance when you browse or search for files. However, the larger the cache, the more disk space it uses. Cache preferences help you manage the trade-off between performance and cache size.
100% Preview, also called full-size cache, is a JPEG file that displays the 100% zoom-in. This zoom-in is what you see in a slideshow and in full-screen preview. It is also what you see when you use the Loupe tool in Review mode or the Preview panel. When you use this cached file, you avoid rerendering a 100% image from the original source file. However, it does require additional disk space and initial processing takes some time.
When you use the Loupe tool or 100% zoom, this 100% preview is extracted into memory from the file. The Keep 100% Previews In Cache option allows the 100% preview to be written to the central cache, which is in the following location:
Note: On Windows, turn on Show Hidden Files to see this location. See Show hidden files, folders, filename extensions | Windows XP, Vista, Windows 7.
You can also generate full-size previews for all files in a folder. Click the thumbnail and preview quality button in the Application bar and choose Generate 100% Previews. These full-size previews are only used for 100% zoom and loupe, however. They are not used to display thumbnails, slideshows, and screen previews in less than 100% view. Also, they aren't used in the Preview panel or Review mode when you are not using the Loupe tool.
This option synchronizes central and exported cache data. It generates exported cache files for every folder that Adobe Bridge browses (as long as the folder is not read-only).
The first time Adobe Bridge views a folder, it checks for the existence of an exported cache. If it finds an exported cache, Adobe Bridge imports all the entries into its central cache. After that, Adobe Bridge only deals with the central cache for that folder; any new or modified thumbnails or metadata is stored in the central cache. If Automatically Export Cache To Folders When Possible is selected, Adobe Bridge also updates the exported cache with the newly generated or updated thumbnails or metadata. But Bridge does not read exported cache data for that folder since the folder exists in the central cache. What does this mean in practice? It comes into play when multiple instances of Adobe Bridge -- on the same or different computers -- view the folder. For example:
If you don't want to fill disk space with exported caches for every folder Adobe Bridge views, deselect this option. You can export the cache manually for any individual folder by choosing Tools > Cache > Build And Export Cache. You could do this step, for example, before burning a folder to DVD.
Location shows the path to the central cache. The Adobe Bridge CS3 central cache is in a different location from Adobe Bridge CS4 and CS5. Adobe Bridge CS4 and CS5 do not read the central cache from Bridge CS3.
Each file and folder that Adobe Bridge caches uses one database record. A database record includes one or more JPEG files that Adobe Bridge generates to display thumbnails and previews. The cache can store to 500,000 records; the default cache size is 100,000 records. Increasing the cache size can improve performance, but a bigger cache uses more disk space.
Compacting the cache removes obsolete database records and the JPEG files associated with those records.
Purging the cache deletes all thumbnails and previews from the central cache.