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aledeniz
aledeniz
Participant
December 13, 2018
Answered

Rebuilding previews from embedded/sidecar to minimal?

  • December 13, 2018
  • 1 reply
  • 2775 views

I am a complete newbie with Lightroom Classic CC.

I am reading the reference, viewing the tutorials, and following Matthew Pizzi's Lightroom CC Fundamentals course on PluralSight.

To better understand the Catalog requirements, I have imported ~108,000 photographs in a single catalog, selecting embedded/sidecar as preview type.

My workstation (Windows 10 on Intel i7, media drives on dedicated SAN in RAID 10, all enterprise class hardware) took a couple of days to complete that.

The resulting Lightroom Catalog Previews.lrdata folder is 323 GB. For a number of reasons, I think this is higher than I'd like [1].

I do wonder if there is a way to rebuild the previews as minimal, or if I have to start a new catalog and import from scratch.

Or should I instead try to rebuild the previews as standard, selecting medium or low quality?

Also, what happens when there are not embedded/sidecar previews? Does the import fall back to standard?

[1] of those ~108k, ~44k are my personal ones (half RAW+JPEG, half JPEG, I think I may have not imported the JPEG version of the RAW ones), while ~64k (all JPEG) are representative of a job (a smallish one, so I added my own pictures to make the exercise more representative).

Corrected a typo. Message was edited by: Alessandro Riolo

This topic has been closed for replies.
Correct answer cmgap

You won't have to start a new catalog to rebuild the previews file with minimal if that is really what you want to do. Keep in mind that minimal previews are the lowest quality preview and you won't be able to zoom in. You can however choose to rebuild, select minimal to reduce the file size and create Smart Previews selectively.

If you want to rebuild your preview files:

- Quit Lightroom, locate the previews file (Previews.lrdata) in your Lightroom folder and rename the file. You'll delete it later once you've confirmed the new preview file is as expected.

- Restart Lightroom > Select all images in catalog and go to Library menu > Previews > Build Minimal-Sized Previews

Delete the old previews file after checking to make sure that all is working as expected.

1 reply

cmgap
Community Expert
cmgapCommunity ExpertCorrect answer
Community Expert
December 13, 2018

You won't have to start a new catalog to rebuild the previews file with minimal if that is really what you want to do. Keep in mind that minimal previews are the lowest quality preview and you won't be able to zoom in. You can however choose to rebuild, select minimal to reduce the file size and create Smart Previews selectively.

If you want to rebuild your preview files:

- Quit Lightroom, locate the previews file (Previews.lrdata) in your Lightroom folder and rename the file. You'll delete it later once you've confirmed the new preview file is as expected.

- Restart Lightroom > Select all images in catalog and go to Library menu > Previews > Build Minimal-Sized Previews

Delete the old previews file after checking to make sure that all is working as expected.

aledeniz
aledenizAuthor
Participant
December 16, 2018

I did follow your advice. Sort of, but worked Thank you.

When I started I had more than 122k+ photos in the catalog.  I set the quality of the standard previews to low, size 1024 px. I have also found somewhere the option to enable the usage of GPU.

I quit Lightroom, I renamed the entire folder as Lightroom Catalog Previews.lrdata.bak, and then I built standard previews.

The new Lightroom Catalog Previews.lrdata folder was generated much faster, and I was actually able to use the workstation while the preview generation was being performed. At the end of the process the folder was 19 GB, as opposed to the 346 GB of the previous folder (after I discarded all 1:1 previews). That's quite an improvement.

As a side note, the GPU in this workstation is not great (Intel HD 4600), Lightroom was barely using it (less than 8% GPU usage thorough the process), but the performance of the previews generation process were seriously improved nonetheless.

cmgap
Community Expert
cmgapCommunity Expert
Community Expert
December 16, 2018

Thanks for taking the time to update the post. If you find that some of the develop tools are sluggish (spot healing for example) you can turn off Use GPU in the Preferences > Performance tab.

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