Catalogs Delete previews for photos stored on external drives not always connected?

[cavics]

Lightroom Version Number

13.4

Operating System

1. Windows 11

I believe that I know the answer to this but want to confirm.

I'm a working photographer with huge Lightroom catalogs (517,000 images in one, over 2,000,000 in another).

My catalogs are on a 1TB SSD and the preview files take up a lot of space. I'd like to delete some of them.

My photos are stored on external hard drives that are disconnected at times as I have a number of them

Question #1: I assume that if I delete previews and disconnect particular drive, I will see no images when I look in the folders fir that drive, right?

Question #2: Also, I don't see an option to place my previews on an external drive. Do my previews have to reside on the same drive as the catalog?

Question #3: Is there a way to delete previews from within Lightroom? if so, I could delete the previews of the photos that on drives that I keep connected.

Thanks!

 

[Califdan]

Question #1: I assume that if I delete previews and disconnect particular drive, I will see no images when I look in the folders fir that drive, right?

Correct. You will see empty gray cells. However all the metadata will be there but without seeing the preview it would be hard to know which image you have sleclect unless you printed a contact sheet ahead of time but that would probably not be too practical.

Question #2: Also, I don't see an option to place my previews on an external drive. Do my previews have to reside on the same drive as the catalog?

The previews need to be in the same folder as the catalog. But, that folder can be on an external drive.

Question #3: Is there a way to delete previews from within Lightroom? if so, I could delete the previews of the photos that on drives that I keep connected.

it depends on what type of Previews you create. But for minimal, and standard peviews the answer is no. I don't have LrC open right not but I believe you can set a retention time for 1:1 previews and can delete them on demand but I'd have to check.

Thee may be plugin's that can read the catalog looking for attributes on images (for example what drive they are on, or some keyword you apply) and then generate a list of previews files (and path to them) to be deleted which an external program could then read and delete those preview image files. I don't know of any but perhaps one is out there.

 

[vbnut]

The Library>Previews menu (on Windows) contains menu items "Discard 1:1 Previews ..." and "Discard Smart Previews ..." that will (I believe) delete those previews. You can select a set of images to discard the previews only for those images. If you have only one image selected, LrC will ask: "Discard the ... Preview for all nnn photos or only the selected one?" (where nnn is the number of photos in the grid filmstrip.

 

[Paul McFarlane]

Jeffrey Friedl has a plugin that can delete standard previews; I've never used it, but it may be worth looking at:

https://regex.info/blog/lightroom-goodies/bag-o-goodies#delete-cache

Look for 'Delete Cached Previews for Selected Photos'

 

[Johan Elzenga]

The Library>Previews menu (on Windows) contains menu items "Discard 1:1 Previews ..." and "Discard Smart Previews ..." that will (I believe) delete those previews. You can select a set of images to discard the previews only for those images. If you have only one image selected, LrC will ask: "Discard the ... Preview for all nnn photos or only the selected one?" (where nnn is the number of photos in the grid filmstrip.

You can only discard 1:1 previews this way, not the standard previews. ‘Smart previews’ is a very bad name, because they are not previews at all, so they have nothing to do with this. They are proxies for the original images.

 

[Gnits]

I would forensically decide / calculate what your default preview size might be.

I have a well specified machine, but it positively started to slow when I upgraded f my camera from 40 MB to 60 MB a7RV raw files.

While I have a 4k screen, I rarely use full screen in Library or grid view, especiallt taking into account the various side panels. So I changed my default preview size to 1680. It made a difference to the interoperability of LR on my machine.

In your case, it may have an impact on the storage required for your previews.

Also, in your case.... maybe the easiest answer might be to upgrade from 1TB to a 2 or 4 TB SSD. They are getting cheaper and faster.