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A
ATEriksen
Known Participant
November 14, 2023
Question

Downgrading preview quality and size

  • November 14, 2023
  • 1 reply
  • 1126 views

Hello,


Mods:
I consider this problem a bug since previews settings changed and no regeneration of previews happen on previously built previews, even if it's asked for manually in the menus.

Problem:
Standard previews was set too high before facial recognition work was done on half million images. Nothing happens in Lightroom process tree if I lower quality and pixels then regenerate "standard preview" and select all. Program probably assume I don't need to rebuild the older standard previews since they exist, even if settings changed. Or... it should work but it doesn't.

 

I have MANY files so I really don't want to go through and delete Master_Catalog-v13 Previews.lrdata file, rebuild ALL previews, and possiblly losing all facial recognition data while at it. Adobe Support couldn't promise i lost the facial recognition data or not when deleting this file. 

 

What outcome I wish for:

Set lower standard preview quality and pixel dimentions so that I can save some space on my half million older images, then do smart previews or something else etc on newer more current files. I could also use embedded or sidecard images on my older images, but I can't see any options to sleect using embedded or sidecard after the fact. 

Previous Catalog settings:
Standard preview size: (Auto) 3072px
Quality: High
Delete 1:1: Every 30 days

Current Catalog settings:
Standard preview size: 2048px
Quality: Middle
Delete 1:1: Every 30 days

Simply upgrading disk because "storage is cheap" isn't a solution I'm going for,  it is also an inefficient way to solvie things in the long run. Image data accumulates a lot, and old images doesn't need to be full size in their previews after some years.. I think Adobe and application should be more ECO friendly and save environment, users money and users frustration when they can. This means either regenerate new standard previews if settings has changed since last time, especially if user request it - OR - at least ask if user like to rebuild the standard previews with the new settings.

Best regards,

Aleksander

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    1 reply

    A
    ATEriksenAuthor
    Known Participant
    November 14, 2023

    I have to add..

     

    Adobe couldn't confirm if moving Master_Catalog-v13 Previews.lrdata would detach keyword (name of face) from image data (face location in file), so I'm not eager to try moving it either.. I'm also having second thouhgts about moving/deleting preview file and regenerate lower resolution previews, because if face was at a certain point in a 4096px document, it would certainly not be in the same location at 2048px if they used pixel location as identifier. I'm guessing facial recognition is linked to the preview in some way.

     

    Weird that this regenerate standard preview doesn't work on previously generated ones with new settings, the option has been there since first version of Lightroom AFAIK.

     

    Anyway. I hope Adobe fixes this, because I can't think this is how it was designed, it has to be a bug..

     

    Regards,
    Aleksander

      GoldingD
      GoldingD
      Legend
      November 14, 2023

      About the previews.lrdata file:

      https://phototacopodcast.com/is-it-safe-to-delete-lightroom-previews-lrdata/

       

      A
      ATEriksenAuthor
      Known Participant
      November 14, 2023

      You could consider copying the catalog, then testings out on the copy. Naturally have good complete backups.

       


      TLDR: If I get time I'll try it on my wifes PC, but I kind of trust Adobe on this one. 

      I did ask Adobe spesifically about these issues and also asking them if facial recognition used standard previews to register faces. Then I asked if moving or deleting preview was going to unlink /remove face  recognition data, along with other questions on this issue.

      The support guy made me wait about 10 minute while he was checking dev documentation and asking his closest seniors, but found nothing about how this impacted facial recognition data. The support guy had to put me on wait some hours until devs and other seniors could answer him because this was an issue that he couldn't even find answer to and wanted to solve asap. 

       

      The reply you see is when he asked his devs/seniors, and they confirmed standard previews is used / linked to facial recognition since deleting or moving the file would unlink/remove the face data, so I'm not tempted to waste time trying to overprove this to see if Support is wrong or lying. I'm also afraid that I'm going to hamper the facial recognition in some other way when changing catalogue or messing up my Cloud Sync while at it. This is also a production system, so I really don't have time or patience to mess around then having to fix everything again.

      There is something to be said about faces located at a X,Y in 3072px long edge preview vs 2048px preview when changing the resolution. Most likely it wont be in the same place anyway, so the better option is to make sure application resize preview and keep the box/link over the face when preview changes. 

       

      It is not like I'm out of space right now or have dire needs. I can survive until they fix this issue within resonable time so that we don't not needed to whack around catalogue system files - potentially breaking anything. I also see so many posts on this issue that it kind of needs to be resolved properly soon. The function has been there for about two decades, with many posts on similar support cases, where only solution is to delete or move previews file. It's not become any better for anyone after all this time, so I will make sure this change for the better so we all can have a better experience with previews 😀 

      Best regards,
      Aleksander


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