Lightroom: How do I manage excess LR previews?

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  • Updated 4 years ago
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Could we have a utility in LR to get rid of the excess previews that accumulate with time. I only generated mine about a month ago (80k) and already have over 200 more previews than I have files.

I also find previews that do not have the last part of the preview filename - the long part after the last -. Why does this occur?

Time to regenerate them again - to get a clean set!! It's very tedious.

bob Frost
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Robert Frost

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Posted 4 years ago

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Rob Cole

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Make sure your standard previews are small enough that when Lr deletes 1:1 previews, they are actually deleted - that should take care of excess storage.

Not sure what the extra files are about - I have 420 extra.

PS - I dunno why you'd not get a full filename - first part is UUID, and second part is digest - never heard of missing digest, maybe those are bogus entries (dunno). I just checked: all my preview filenames are the same length: 76 characters including lrprev extension.

Smart previews have UUID but no digest (dng extension).

PPS - When you delete a photo (or remove from catalog), the previews should go with it (smart previews are deleted upon startup *iff* it's been over an hour since photo deletion, but I'm assuming we're talking about regular previews, no?).

PPPS - If you really must delete regular previews selectively, standard size I mean, you can do so using Preview Exporter's "Discard Lib Previews" feature. Note: it operates on a copy of your previews (and requires restarting Lr) so probably isn't something you'll wanna do too often..

Rob
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Robert Frost

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The quickest way to solve this was to use LR to export all the images as a new catalog, with previews. Didn't take long. Better than a day or so re-rendering previews.

Any disadvantages of doing this, Rob? Collections all seem OK, your plugins are OK. And I now have exactly the right number of previews.

Bob Frost
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Rob Cole

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Not all publish service stuff gets exported / imported, which could cost you some setup time and/or republishing a whole buncha stuff to get back to where you were before - otherwise no problem.
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Robert Frost

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That's Ok then, since I don't use Publish stuff.

Bob F.
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Robert Frost

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Just had a look at an old previews.db, and the previews without a digest at the end of their filename are sRGB and have a 'thumbnail' quality, compared with the rest of the previews that have a digest, are AdobeRGB, and are 'standard' or 'final' quality.

Does that mean anything to you, Rob?

Bob Frost
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Rob Cole

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Yes, it means "something" to me, but I can't give a real explanation. I thought @Lr4, all newly created previews would be AdobeRGB, so unless those previews are from Lr3 or earlier (I think you already said they were recently rebuilt), I can't explain.

I suppose it's possible that the smaller thumbs are still being created in sRGB (e.g. are made from extracted sRGB preview when it's already handy), for interim or even permanent use, but now I'm just guessing. If for interim, then it's starting to sound like Lr is not cleaning up after itself.. - take with salt, I'm out on a limb...
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Victoria Bampton - Lightroom Queen, Champion

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Thumbnails captured from the file, before LR creates its own preview, would likely be sRGB. I can't explain why they're still there, but that's the most likely cause.
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Robert Frost

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Thanks to both of you for your comments. That led me to look at the datestamp of the 'short-name' previews, and then select images edited on those days. It seems that some/most/all of them were used in a book that I was editing last week. I saved the book to pdf at least once, so that might account for the sRGB profiles. So as Rob suggested, LR might not have been cleaning up after itself while making the book. Seems plausible!

Anyhow, as I don't use Publish, saving the images and previews out to a new catalog seems to solve the problem of excess previews and doesn't take long.

BUT it would still be good if Adobe had a utility alongside Optimise Catalog that Optimised Previews properly.

Bob Frost