Lightroom Preview file location

[Paul2660]

With Lightroom 1.4, on a PC, I am trying to understand where the image preview cache is located.  I am exporting raw files from a disk, not creating a library under Lightroom.

I have read something about lightroom using the existing jpg embedded within the raw, but wanted to ask for more details.  

Coming from Capture 3.7.8 or Capture 4.1.  If you point either of these tools to a folder of raw files on your disk, then the first thing they will do is create a preview file of each raw file in that particular folder.  The Capture 3.7.8 previews are quite large, Capture 4.1 appear to be much smaller, but still both need to be removed over time to free up space.  This is not to be confused with a much smaller file that is created for each raw you develop, this file will keep the information for editing changes WB, Exp, sharpening, etc. you made to the file.

Thanks
Paul C

[Nat Coalson]

The Lightroom previews (thumbnails, standard and 1:1) are stored in the same folder with the database (catalog).

When importing files, LR will use a JPG for the small (thumbnail) preview, if it finds one. But as you work within LR, the previews get continually updated in the ... Previews.lrdata package.

If you're using DNG, when you Save Metadata out of Lightroom, the JPG preview within the DNG gets updated.

[Paul2660]

Thanks,

If I remove files from Lightroom, will the preview be removed also, and the catalog updated?  

Is the database catalog, one big file? or does lightroom generate one everytime you import new files to the disk?  

Paul C

[francofit]

Thanks,

If I remove files from Lightroom, will the preview be removed also, and the catalog updated? 

Is the database catalog, one big file? or does lightroom generate one everytime you import new files to the disk? 

Paul C
[{POST_SNAPBACK}][/a]

The database catalog is one file where all metadata, keywords and similar info are stored and continually updated as you modify them and (on PC) is the file named:  "<catalog_name>.lrcat"
By default is "Lightroom Database.lrcat" and it does not contain preview visual infos.
("<catalog_name>.lrcat").


The thumbnail view infos are stored (and again automatically updated when needed) in another file under folder "<catalog_name> Previews.lrdata", named: "thumbnail-cache.db".  
By default the complete PathName is: "Lightroom Database Previews.lrdata\thumbnail-cache.db".
("<catalog_name> Previews.lrdata\thumbnail-cache.db").


The actual standard and full size previews are stored under a rich structure of folders-subfolders ("0".."9", "A".."F" under the same above mentioned Previews folder) and each image has one file "<very-very-long-fileName>.lr-preview.noindex".
("<catalog_name> Previews.lrdata\0\0A7D\0A7D7461-E81F-4827-B130-3A1929EE6029-867a97fe8396e14021e10de6ca28550d-67.lr-preview.noindex")

Based on my experience and observation these preview files are automatically cleaned-up when you remove images from the catalog, not always immediately but for sure yes over time.
I think that running the Optimize Db command speeds-up the cleaning-up;  I am not sure about this but anyway I run the Optimize regularly after significant add/deletes  and I have so far always seen that the total "Previews" disk occupancy is kept automatically under control based on the add/delete of images in the catalog.


Hope this answer your questions.

P.S.: you may wish to have a look at this thread [a href=\"http://luminous-landscape.com/forum/index.php?showtopic=23811&st=0&p=180369&#entry180369]File Madness[/url] for further detailed discussion on the LR Previews (and Backups) structure and function on Windows.

[Paul2660]

Thanks for the detailed info.  This is just what I was looking for.

Thanks