# Moving a Catalog back and forth, what about syncing of the 1:1 and/or Smart Previews?



## braver (Aug 25, 2018)

I've been generating 1:1 Previews always, per Peter Krogh (and embedded full-size previews into DNGs as I convert to it).  Now I have a dedicated SSD RAID 5 array for the catalog connected to the desktop iMac Pro, which uses about 2.5TB -- 6GB for the catalog itself, 2.2TB for Previews and 0.3TB for Smart Previews.  I also use SSD RAID arrays for RAW ingestion  (virgin backups) and main photos (DNG conversions).  Backups go to HDD RAID arrays and tape and everything is whirring along beautifully.

I'd like to rate/organize/develop/publish from the laptop though, sometimes.  I'm very good with tooling so could rsync the catalog itself back and forth without hopefully losing the latest edits.  That will require I leave the 1:1 Previews on the RAID while I sync only Smart Previews to the MacBook Pro (got 2TB of SSD so fits a lot but not all).

The question is, say I only copy Smart Previews on MBP.   Do I need to care about syncing the previews back to the iMac?  I pride myself for iMac having Smart Previews and 1:1 Previews for every main photo.  But I'm not worried if some previews are out of sync with the main image edits.  I don't want preview files to collide though or become somehow duplicated.  Their subdirectories are opaque, with hexadecimal names, and it's not clear to me how I can easily verify, using the command-line tools, whether a preview directory is newer or older or is OK.  Is it enough to  move the catalog around and let previews be not to inflict damage on the overall catalog directory eventually?

For publishing, only one catalog can be synced with Lr Mobile, and I have that going to iMac of course that's always on and a dedicated RAID array is receiving those.  So I'm not going to have the visiting MBP catalog synced.  But If I want to publish from the laptop, is it OK to do so from the visiting catalog?  Say to SmugMug/500px/Facebook, etc.?  What will happen to the published status, and will the iMac pick up where I left it on the MBP once I rsync the catalog file itself back from the MBP to iMac?


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## Jim Wilde (Aug 26, 2018)

No, you don't need to sync the library previews back and forth, Lightroom will figure out for itself what it has and doesn't have (rebuilding new previews as needed). Note that only Standard previews are built by default, 1:1 previews only get built on demand (user request or when zooming to 1:1).

As an aside, do you really need to retain 1:1 previews for your entire library? They're useful when doing the initial culling, but after that?


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## braver (Aug 26, 2018)

I started keeping 1:1 Previews per Peter Krogh in 2007, when it was time-consuming to generate them on the fly.  I kind of stuck to it and it just pleases me to know I have them all and I almost never need to generate anything -- assuming it speeds up rendering.  Although with the maxed out 18-core iMac Pro that probably is not really necessary...


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## Jim Wilde (Aug 26, 2018)

After you edit a picture, do you then manually build a 1:1 preview? The one you build on import will be thrown away by LR as soon as you start to edit an image, which means having to force LR to rebuild it when editing is completed.


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## braver (Aug 26, 2018)

Jim Wilde said:


> After you edit a picture, do you then manually build a 1:1 preview? The one you build on import will be thrown away by LR as soon as you start to edit an image, which means having to force LR to rebuild it when editing is completed.



I guess I very rarely edit images, and in all cases very few of the 300K will ever be edited.  So I'm not sure whether I'm gaining much but I do have them...  Also, per Peter, I'm building the DNGs with 1:1 previews.


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## braver (Aug 26, 2018)

I must say that the motivation to do this is obviated by LrCC, which would both keep a local Smart Preview cache and also let me rate and organize albums as well as edit them locally on the laptop and sync back.


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## Jim Wilde (Aug 26, 2018)

braver said:


> I must say that the motivation to do this is obviated by LrCC, which would both keep a local Smart Preview cache and also let me rate and organize albums as well as edit them locally on the laptop and sync back.


Yes, but just be aware that some things do not sync between LRCC and LR Classic, notably keywords and location data.


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## braver (Aug 26, 2018)

Jim Wilde said:


> Yes, but just be aware that some things do not sync between LRCC and LR Classic, notably keywords and location data.



That's good to know.  I was surprised to see, in LrCC keyword pane, just a text box to enter a keyword -- no help, completion, ontology, nothing?

Also I'm disappointed to find I cannot add images to various albums easily.  I use albums for Adobe Portfolio, external publishing, etc.  The DAM options of LrCC are extremely limited.


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## PhilBurton (Aug 26, 2018)

braver said:


> That's good to know.  I was surprised to see, in LrCC keyword pane, just a text box to enter a keyword -- no help, completion, ontology, nothing?
> 
> Also I'm disappointed to find I cannot add images to various albums easily.  I use albums for Adobe Portfolio, external publishing, etc.  The DAM options of LrCC are extremely limited.


This thread may be of interest to  you.   Best (or good) way to synchronize one catalog on 2 devices without the cloud. 

Phil Burton


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## Dan Marchant (Aug 27, 2018)

braver said:


> I've been generating 1:1 Previews always, per Peter Krogh (and embedded full-size previews into DNGs as I convert to it).


Can I ask why exactly you are going to all this trouble to create 1:1 preview (which take up quite a bit of storage space)? 1:1 Preview are only used during editing and you have stated that you don't edit your images. So this would seem to be a complete waste of time and storage. To then worry about syncing these worthless files between two machines would seem to be adding further cruft to an already overly complex (and unnecessary) workflow.


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## Johan Elzenga (Aug 27, 2018)

Dan Marchant said:


> 1:1 Preview are only used during editing and you have stated that you don't edit your images.


No, that is not correct. The Develop module uses its own, different previews. The 1:1 previews you can generate in the Library are used when you zoom in to 100% view, not for editing.


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## braver (Aug 27, 2018)

Dan Marchant said:


> Can I ask why exactly you are going to all this trouble to create 1:1 preview (which take up quite a bit of storage space)? 1:1 Preview are only used during editing and you have stated that you don't edit your images. So this would seem to be a complete waste of time and storage. To then worry about syncing these worthless files between two machines would seem to be adding further cruft to an already overly complex (and unnecessary) workflow.



I admit it is a habit that made sense at some point and is now perpetuating itself.  My assumption was that Lightroom Classic is using all the preview sizes in the Library module, where I spend 99% of the time anyways, making it faster to browse at any resolution.  The Classic added Auto resolution for 1:1 that shows as 5120 for iMac Pro.   I was always setting that to max size.  FWIW I thus have the rendered JPEGs of all the DNGs already hanging around...


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