# Can multiple users view Lightroom catalog from different computers?



## JohnKendrick (Aug 7, 2016)

Can a Lightroom user on one computer using Lightroom read the catalogue of another Lightroom user on a second computer? Can either work on the catalog of the other?

A nonprofit with which I am connected as several LR licenses. Several staff members will be working on a large photo collection. The work will proceed best if each staff member can access the same catalogue from their own computer.

John Kendrick


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## Johan Elzenga (Aug 7, 2016)

No, Lightroom cannot use a catalog on a network disk.


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## JohnKendrick (Aug 7, 2016)

JohanElzenga said:


> No, Lightroom cannot use a catalog on a network disk.


Got it. Then the next question. I understand LR to keep all cataloguing information about specific photos in its catalogue. Not attach it to the photos themselves. Is there a way to attach it to the photos?

John Kendrick


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## Johan Elzenga (Aug 7, 2016)

JohnKendrick said:


> Got it. Then the next question. I understand LR to keep all cataloguing information about specific photos in its catalogue. Not attach it to the photos themselves. Is there a way to attach it to the photos?



Not all of it, but most of it. Select the image and choose 'Metadata - Save Metadata to File'. If you import this image in into another catalog, the metadata you just saved will be read. If the image is already imported in another catalog too, then the menu 'Read Metadata from File' will update that catalog with these metadata. Tbis way you could keep different catalogs in sync, but I doubt this would work for what you want. Everybody would have to apply 'Read Metadata' before starting to work, because you never know what other people did. And you would have to repeat this frequently, because you don't know what other people are doing right now. Even then it's just a matter of time before two people work on the same image at the same time...


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## clee01l (Aug 7, 2016)

JohnKendrick said:


> Got it. Then the next question. I understand LR to keep all cataloguing information about specific photos in its catalogue. Not attach it to the photos themselves. Is there a way to attach it to the photos?
> 
> John Kendrick


This can cause unnecessary confusion.  What I think needs to be done is a Master catalog is managed by one person. Individuals get subsets of that master catalog to works as assigned.  Periodically the subordinate catalogs are "imported as a catalog" into the master catalog to consolidate the everything.


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## Johan Elzenga (Aug 7, 2016)

I think it depends on what these people are doing with the images, and if they need access to the same images around the same time. If each person works on a distinct subset of images, then you could use the method Cletus describes. If people need to work on the same images around the same time however, using subset catalogs won't be a workable solution either. Very soon two or more people will have edited the same image, so consolidating everything by importing the subset catalogs again will create havoc on this work. In this case I simply don't think there is a good solution in Lightroom. You need to use something else.

If people only need to access the images to export a jpeg for example, but they don't edit images and/or add metadata like keywords, then you could give each person a (full) catalog that is linked to the same images. One administrator will be responsible for making any necessary edits and/or metadata changes, and then you could either use the 'Save Metadata' / 'Read Metadata' method to sync the catalogs from time to time, or just distribute a fresh replacement copy of the catalog.


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## JohnKendrick (Aug 7, 2016)

Thanks. Since these are all beginning LR users, the best solution I can see is that leave all the photos and the catalogue on the one computer and each staffer works on it there. Will also have to explore other solutions.

John


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## Linwood Ferguson (Aug 8, 2016)

JohnKendrick said:


> Thanks. Since these are all beginning LR users, the best solution I can see is that leave all the photos and the catalogue on the one computer and each staffer works on it there. Will also have to explore other solutions.


Absolutely.

The problem with the internet is that there are a lot of computer savy technophiles around, and if someone says "you can't do that" we find a way.  The "way" may be risky, unstable, and complex, but there's almost always a way. 

Like the sky diver who figured out how to jump without a parachute, just because you can, doesn't mean you should.


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## JohnKendrick (Aug 8, 2016)




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## PhilBurton (Aug 8, 2016)

Ferguson said:


> Absolutely.
> 
> The problem with the internet is that there are a lot of computer savy technophiles around, and if someone says "you can't do that" we find a way.  The "way" may be risky, unstable, and complex, but there's almost always a way.
> 
> Like the sky diver who figured out how to jump without a parachute, just because you can, doesn't mean you should.



Maybe so.  You could access the catalog across the network, and it might seem to work, that is, until it doesn't with some "silent corruption."  Maybe, just maybe, that technophile understands the issues can has devised a workaround, but if you're not that technophile, then don't go there.

Phil


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## Victoria Bampton (Aug 10, 2016)

What do they actually need to DO to the photos?  I'm just wondering whether having a single 'master' catalog on one machine, syncing all of the photos to the cloud and then the other people using the web interface might work for them.


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## gYab61zH (Nov 3, 2016)

Could you elaborate on this Victoria? Like others I am very frustrated that there appears to be no way to work on the same catalogue using different computers because catalogues cannot be networked. Is there still no work-around? The only approach I can think of to the problem sketched above is to back up the catalogue after every session and sync the backup folder to my other machines (where they need to be unpacked first) on which I also backup after every session. 

Would the Adobe Creative Cloud be a solution? Can it handle a catalogue with 50000 images and if so would that not be prohibitively expensive?

PS. I did try to read up on this on the Adobe website but found it almost impossible to find this info in the midst of tons of advertising.


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## Gnits (Nov 3, 2016)

One option to consider (and far from the ideal of a true multi user networked application).

Install Lr and its Catalog on a designated networked computer (call it TheLightroomMachine).  Separately, use a remote access application (such as TeamViewer) so that individuals from different PCs can use the remote access to use Lightroom on TheLightroomMachine.  You can keep all the images on a network drive and you will need to develop protocols to cover the following scenarios: 

1. How images are added to the Network drive
2. No images can then be moved/deleted unless moved/deleted within Lightroom.
3. Agree a schedule or rota when people can use (remotely) or physically TheLightroomMachine.

You should appoint one individual to be the official administrator, to manage the major data flows, importing and exporting, etc..

This is far from ideal, only provides single user access at a time, but does provide a better option than trying to synch or manage multiple catalogs on multiple machines.

TeamViewer is an enterprise level product and has a free version for non commercial use. Others may wish to suggest alternatives to TeamViewer.


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## gYab61zH (Nov 3, 2016)

Thanks, I guess that would work. In fact, unlike the OP, I do not need access by different people since I am the only one using LR, but I am not always behind my desktop, so need access from work and the laptop. So far I have shied away from remote access apps because the ones I have used tend to rescale the original screen to such an extent that everything becomes really tiny on a laptop. But I do not know TeamViewer and will check it out.


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## Gnits (Nov 3, 2016)

I use TeamViewer a lot.  It works on Mac and Windows (and even mobile devices if you are desperate. It can also work over the internet, so all users do not need to be in the physical environment of the network. I often use it to manage different machines (eg a MacMini) within my home because  it is easier and more convenient to manage from  the comfort of my office and Windows workstation with my favourite keyboard and mouse.


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## Victoria Bampton (Nov 3, 2016)

gYab61zH said:


> Could you elaborate on this Victoria? Like others I am very frustrated that there appears to be no way to work on the same catalogue using different computers because catalogues cannot be networked. Is there still no work-around?



In the scenario mentioned above (multiple people needing access), if you have a CC subscription, one computer can be the 'master' catalog and you can sync the photos to the cloud (50k is fine) and then others can have limited access to the photos either by you sharing your Adobe ID login credentials (allows them to flag, star, organize in collections and do Develop edits in a web browser) or by sharing links to specific collections (allows viewing, low res downloading and 'liking' photos).

If you're the only user, putting the catalog and previews in a paid dropbox account works fine for automatically syncing to other machines. You just have to make sure it's fully synced before you switch machines.


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## Samoreen (Nov 3, 2016)

Hi,

It's easy to make a networked catalog appear as a local one by using the SUBST command (Windows). I won't give you any link to a page explaining this because it's not a good idea...

A Lightroom catalog is an SQLite database which supports simultaneous accesses from multiple users. Simultaneous "write" accesses are serialized to prevent collisions. However, this is not enough : the client software (Lightroom) must also make sure that the information stored in the database remains consistent. And it is clearly stated that the Lightroom code always assumes that only one user is currently accessing the database at one given moment. S*haring an LR catalog between multiple users is not safe* (at least until Adobe modifies the Lightroom code in order to handle this). Y*ou can be sure that sooner or later, some inconsistencies (if not corrupted data) will appear*.

The approach described by Gnits is correct but you can't guarantee that the necessary protocols will be respected by the users. And even if these protocols are followed, there's another problem to manage : what if different users work on the same image ? This implies using a version management system over the database itself similar to the programs used by software developers working on a common project.

So my advice is : *just don't do it*. Multiple users accessing the same catalog is not something that belongs to the Lightroom specifications.


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## gYab61zH (Nov 3, 2016)

Victoria Bampton said:


> If you're the only user, putting the catalog and previews in a paid dropbox account works fine for automatically syncing to other machines. You just have to make sure it's fully synced before you switch machines.



I am the only user, but I vaguely remember warnings some years ago against this setup. Also with a 128 Gb preview file the syncing may be a bit slow, particularly if the program tries to sync the whole file instead of the changed previews within it (I am uploading it now but with my connection it could take up top a day before it has been uploaded). And would I be able to actually use LR without direct access to the images or do I need 1:1 previews for that, which would make the preview file enormous.

Perhaps I should try the CC subscription path after all. You say 50k in the database is no problem but what about that number of images; they take up almost 1 Tb. Is such storage part of the deal or do you need to pay for it separately? And what about privacy?


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## Johan Elzenga (Nov 3, 2016)

Don't worry, the previews isn't a file. It's a package, which is a folder that looks like a file. Dropbox will only sync the changes, not the entire 128 GB. Besides that, Dropbox only syncs the changed bits, so even the catalog file will not be synched again completely, but only the changes inside that file.


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## gYab61zH (Nov 3, 2016)

JohanElzenga said:


> Don't worry, the previews isn't a file. It's a package, which is a folder that looks like a file. Dropbox will only sync the changes, not the entire 128 GB. Besides that, Dropbox only syncs the changed bits, so even the catalog file will not be synched again completely, but only the changes inside that file.


Thanks Johan. I am not actually on Dropbox but use the much more secure Sync.com, but since it is telling me that it is syncing just short of 50000 files I assume the same applies here. What about working with LR without direct access to all the images?


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## Johan Elzenga (Nov 3, 2016)

Working with Lightroom without access to the original images is possible by using smart previews.


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## gYab61zH (Nov 3, 2016)

JohanElzenga said:


> Working with Lightroom without access to the original images is possible by using smart previews.


I have never used smart previews before, and consequently had kind of forgotten what they were for, so thanks again. One step closer to a solution.
BTW, with smart previews, who still needs regular previews? Why not simplify things and ONLY have smart previews?


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## Johan Elzenga (Nov 3, 2016)

gYab61zH said:


> I have never used smart previews before, and consequently had kind of forgotten what they were for, so thanks again. One step closer to a solution.
> BTW, with smart previews, who still needs regular previews? Why not simplify things and ONLY have smart previews?



You still need regular previews. Smart previews is a misleading name. They are not previews at all, they are small substitutes for your original images, so something like 'smart raw files' would have been a more appropriate name.


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## clee01l (Nov 4, 2016)

JohanElzenga said:


> something like 'smart raw files' would have been a more appropriate name


They are not RAW files, they are lossy RGB files created using the DNG file specification.


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## Johan Elzenga (Nov 4, 2016)

clee01l said:


> They are not RAW files, they are lossy RGB files created using the DNG file specification.



I know that, but as they are substitutes for your raw files, I still think that some name that makes this clear is better than 'Smart Preview', which suggests that they are previews (which they are not). Perhaps 'Smart Original' or 'Smart Master Image' would do.


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## JohnKendrick (Aug 7, 2016)

Can a Lightroom user on one computer using Lightroom read the catalogue of another Lightroom user on a second computer? Can either work on the catalog of the other?

A nonprofit with which I am connected as several LR licenses. Several staff members will be working on a large photo collection. The work will proceed best if each staff member can access the same catalogue from their own computer.

John Kendrick


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## johnbeardy (Nov 4, 2016)

I agree about the confusion caused by calling them "previews", but I think Adobe should also have avoided words like "master" and "original" because of their ability to mislead. I don't particularly like "proxy" but I've not found a better term.


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## Johan Elzenga (Nov 4, 2016)

Agreed, "master' or 'original' can also be misleading, and people may think they can trash their 'dumb originals' if they use smart ones... I don't like 'proxy' either, especially because many non-native English speakers may have no idea what that means. Maybe 'smart photo'?


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## gYab61zH (Nov 4, 2016)

I still do not understand. The Adobe video on the subject warns that some edit operations should be treated with some caution because your ability to zoom in is limited to the size of the lossy dng files used for this purpose. That suggests to me you are looking not at a preview but the lossy dng file. So why do we still need previews?


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## Johan Elzenga (Nov 4, 2016)

gYab61zH said:


> I still do not understand. The Adobe video on the subject warns that some edit operations should be treated with some caution because your ability to zoom in is limited to the size of the lossy dngfiles used for this purpose. That suggests to me you are looking not at a preview but the lossy dng file. So why do we still need previews?



Because that lossy dng file acts as a substitute for the original. Just like the original is not altered by Lightroom when you edit the image, so isn't that DNG file. Lightroom stores its edits in the catalog. To show you what you are doing, Lightroom must generate a jpeg-preview that includes those edits. *That is what you are looking at* and that applies no matter if you use the original data to generate the preview or 'smart preview' data. That is why 'smart preview' is such a misleading name. It not a preview at all, it has nothing to do with previewing.


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## Johan Elzenga (Nov 4, 2016)

BTW, you can easily test this yourself. Create a new catalog and import say 100 photos into that catalog. Generate smart previews as well. Make some edits to the images, give Lightroom time to update the previews and then stop Lightroom. Open the new catalog folder and delete the 'previews.lrdata' file, but leave the 'smart previews.lrdata'. Start Lightroom again. What you will see is that initially the catalog has lost all its previews. You'll see an empty grid. Then Lightroom will start rebuilding the previews. Now look inside that catalog folder. Lightroom has re-created the 'previews.lrdata' file, proving that smart previews are not a substitute for normal previews. They are something entirely different.


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## johnbeardy (Nov 4, 2016)

JohanElzenga said:


> I don't like 'proxy' either, especially because many non-native English speakers may have no idea what that means.



And you think native English speakers will know what it is? But that is its great merit - people have to scratch their head and won't just slip into thinking it's an original photo or a preview.


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## Johan Elzenga (Nov 4, 2016)

johnbeardy said:


> And you think native English speakers will know what it is? But that is its great merit - people have to scratch their head and won't just slip into thinking it's an original photo or a preview.



LOL. But if they know what a proxy-server is, they may think it's an exact copy of the original photo...


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## gYab61zH (Nov 4, 2016)

JohanElzenga said:


> Because that lossy dng file acts as a substitute for the original. Just like the original is not altered by Lightroom when you edit the image, so isn't that DNG file. Lightroom stores its edits in the catalog.


The last part, not quoted here, I can follow, even if it seems somewhat superfluous to me to have to work with both a jpg as a preview and a dng. Why not just use the jpg preview file as a stand-in for the real image just as a dng is used in this way. That would certainly keep the files a lot smaller. I still do not understand the above quotation and it is not just in the way you put it, it is also a general LR thing that has long puzzled me. If LR saves edits in the catalogue anyway (how else could we have lossless editing) then why does it even require a stand-in for the original? Why not let us "edit" the preview, save the changes to the catalogue and update the original files as soon as they are available again? I guess I am asking what the whole point of this lossy dng file is.


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## Victoria Bampton (Nov 4, 2016)

gYab61zH said:


> Why not just use the jpg preview file as a stand-in for the real image just as a dng is used in this way.



Ever tried making significant adjustments to a JPEG? The result is completely different to when you apply the same adjustments to raw data. The standard jpg previews therefore wouldn't be a good stand-in for raw files. On the other hand, the smart previews - lossy dog's - give a very close approximation of applying the adjustments to the originals.


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## Johan Elzenga (Nov 4, 2016)

gYab61zH said:


> The last part, not quoted here, I can follow, even if it seems somewhat superfluous to me to have to work with both a jpg as a preview and a dng. Why not just use the jpg preview file as a stand-in for the real image just as a dng is used in this way. That would certainly keep the files a lot smaller. I still do not understand the above quotation and it is not just in the way you put it, it is also a general LR thing that has long puzzled me. If LR saves edits in the catalogue anyway (how else could we have lossless editing) then why does it even require a stand-in for the original? Why not let us "edit" the preview, save the changes to the catalogue and update the original files as soon as they are available again? I guess I am asking what the whole point of this lossy dng file is.



The reason is simple. A jpeg is an 8 bits/color file (by definition), so you would lose too much compared to the 14 bits/color raw file. For some edits it would indeed do: there is no reason why you couldn't apply a crop to the jpeg preview, and sync that when the original is online again. But for other edits, like recovery of highlights, a jpeg is simply not good enough. That is why Adobe uses a small, compressed DNG.


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## gYab61zH (Nov 4, 2016)

Mmm, so what happens when I am trying to edit a jpg file offline? Does LR then generate another jpg or a lossy dng. If the latter, doesn't the same argument hold for the lossy dng as a stand-in for a jpg? Moreover, why use jpgs as previews at all? Why not replace them with lossy dngs that can also substitute as stand-ins for off-line editing?


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## Johan Elzenga (Nov 4, 2016)

gYab61zH said:


> Mmm, so what happens when I am trying to edit a jpg file offline? Does LR then generate another jpg or a lossy dng. If the latter, doesn't the same argument hold for the lossy dng as a stand-in for a jpg? Moreover, why use jpgs as previews at all? Why not replace them with lossy dngs that can also substitute as stand-ins for off-line editing?



Lightroom will still generate a dng if you generate a smart preview for a jpeg original, but you are right: in this case it being a dng does not have any advantage over jpeg. Smart previews were clearly designed with raw files in mind.

The smart preview dng's cannot replace the normal previews, because you'd have to make a choice. Either you use them for parametric editing (as substitutes for originals), in which case they remain unaltered (and so they won't show the edits). Or you use them as replacement for normal previews, but then you need to change the pixels so you no longer have an unaltered replacement for the originals. You can't make an omelet and keep the eggs intact at the same time.


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## gYab61zH (Nov 4, 2016)

No you can't make an omelet without breaking eggs, but you can opt for eggs over-easy or sunny-side up. But seriously, I appreciate the trouble you are all taking to explain this, and things are becoming clearer. To sum up, previews reflect the state of the edited image as recorded in the catalogue; smart "previews" are not previews at all but are rough versions of the original that can be used for parametric editing. So when I am editing an image (proxy or original) on screen what I see is the preview jpg which is immediately saved to the preview container the moment I make a change to it?
As to using dng for jpg, I guess it makes little sense to generate smart proxies in jpg format for jpgs because the difference in size is presumably negligible?


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## Johan Elzenga (Nov 4, 2016)

gYab61zH said:


> No you can't make an omelet without breaking eggs, but you can opt for eggs over-easy or sunny-side up. But seriously, I appreciate the trouble you are all taking to explain this, and things are becoming clearer. To sum up, previews reflect the state of the edited image as recorded in the catalogue; smart "previews" are not previews at all but are rough versions of the original that can be used for parametric editing. So when I am editing an image (proxy or original) on screen what I see is the preview jpg which is immediately saved to the preview container the moment I make a change to it?
> As to using dng for jpg, I guess it makes little sense to generate smart proxies in jpg format for jpgs because the difference in size is presumably negligible?



You've got it!


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