Cleaning Up Lightroom Previews

BACKGROUND INFO

To get the fastest possible speed with Lightroom, I use an Intel X25M SSD to store my Lightroom catalog together with the previews.  The downside to this idea, is that SSDs are expensive.  To keep costs in line, I purchased a small-ish 120Gb drive (that is, it is "small" compared to any regular hard drive in my system, most of which are 2Tb drives).

And it seemed like, over time, the more pictures I took, the less disk space I had available on my SSD.  To the point that I was starting to get worried about it filling up (meanwhile, my Lightroom Catalog was still only 6Gb in size, so I knew it wasn't chewing up all of the space).

Lightroom has an option to limit the size of the Camera Raw Cache (Edit | Preferences | File Handling | Camera Raw Cache Settings) which I also store on the SSD.  There is a purge button on that screen and I would click it from time to time and watch my space free up again.  But it was never really quite the same.  The free space still keep getting lower and lower.

Lightroom also has an option to discard 1:1 previews (Edit | Catalog Settings | File Handling | Automatically Discard 1:1 Previews) after One Day, One Week, 30 Days or Never.  I had it set to One Day and yet my disk space STILL kept dropping.

Lightroom also has an option to optimize the catalog (File | Optimize Catalog).  I have no idea what this does.  It is said to "speed up" the catalog.  I try it from time to time.  But the catalog never really feels slow to me.  And optimizing also doesn't appear to free up much space.

SO HOW DO I FREE UP SPACE?

Well...  I discovered tonight that I had almost 134,000 files in my Lightroom "previews" folder, taking up just over 94Gb of disk space.  And I thought to myself ... how many of those files do I really need???

If a photo shoot is more than 6 months old, maybe I don't need quick access to the previews any more.  What if I delete those files?  (For the wary: Lightroom will automatically rebuild a preview the moment you try to view the file, so this is not dangerous in any way, all I'm doing is trading speed for disk space)

I discovered tonight that Windows 7 has a command called ForFiles that can be run in a batch file.  So I created the following file:

delete_previews_older_than_180_days.cmd:
forfiles -p "d:\users\dwt\pictures\lightroom\Lightroom 3 Catalog-2 Previews.lrdata" -s -m *.lrprev -d -180 -c "cmd /c del @path" 
(all of the above fits on one line in the batch file)

I ran the above command file and my free space jumped from about 4Gb to over 57Gb (having deleted over 52,000 files).  Here's an explanation for what the above command is doing:

ForFiles is the command, the following are the parameters:
-p specifies the root path of the previews
-s tells it to scan subdirectories as well
-m is a filename mask (I used *.lrprev so that only Lightroom Preview files would be deleted)
-d specifies the number of days (-180 tells it to use today's date minus 180 days)
-c "cmd /c del @path" tells it to run the cmd process passing in the command "del @path" for each file found (@path is expanded to the full path and filename of the file found)

If you want to try creating the above command file and test it first without deleting anything... an easy modification would be to change "del" to "dir".  That way when you run the command you will see a list of each of the files found rather than deleting each of the files found.

Be sure to change the path (-p parameter) to match the location for YOUR previews.

Now whenever I want to free up disk space all I have to do is run this command file.  Super easy!  And if I want even more space,  all I really have to do is decrease the number of days (say to -90 instead of -180).

ON A HAPPY NOTE: I found that the catalog itself embeds a thumbnail of each image.  It's not very high resolution.  But it does mean that after deleting the previews and before Lightroom has a chance to regenerate them - if I jump into a folder that I want to see what it is, the thumbnails can help me figure it out quickly.

For Mac users - I have no idea what utilities are available for deleting files by date.  But the idea should be the same.  Feel free to delete your previews, they will come back when you need them.

Before and After (Lightroom Only)

I just thought I'd share one of my favorite photos as a Before and After set.


(click the image to view large)

All changes to the above image were done via Adobe Lightroom only (i.e. no pixel editing has been done via Photoshop or any other software - only Lightroom has been used).

I first straightened the image by simply clicking on the Enable Profile Corrections option. Then I converted to B&W using the Creamtone Preset that comes with Lightroom 3.x. After that I used the graduated filter coming in from the top left and top right corners to add my own vignette to the image. Then I darked with ground with the brush tool. Then I played a bit more with the colors (split tone), contrast and clarity to get to where I liked the image.

And here is the Before image (no specific changes were made for this image, just my regular custom import preset):



In the above image, the couple is being lit by an off-camera flash to my right.

Utah State Capitol - Before / After Lightroom

I love Adobe Lightroom and use it on all of my images. But most of the images I produce are probably closer to straight out of the camera with small tweaks rather than highly modified representations of the image.

Well, tonight I was playing around a little bit with the gradient adjustment layer in Lightroom and thought I'd show off the results of a before/after edit session. It's still nothing too fancy, but it's certainly different from the original:



Both of the above images are from a single raw image processed by Lightroom. The one on the left is just a standard conversion of the capture. The one on the right contains a few more tweaks:

- A couple of gradients were used to lighten the center and darken the top and bottom.

- Another gradient adds some blue to the sky

- Yet another gradient adds some yellow to center of the image (from the capitol building on down)

- While the first includes some Clarity and Saturation, the second uses a lot more Clarity and a little more Saturation.

The images were then brought into photoshop to resize and place them side by side.

Whatdya think? Do you prefer the more hazy picture on the left? Or the brighter, more well defined picture on the right?