I am trying to improve my workflow and was wondering if I could achieve a greater level of performace from Lightroom 4 if I were to create a separate catalog for each time I import.
I have actually tested this by separating some of my photos (around 1200) in to another catalogue as I was worried about putting all my eggs in one basked (incase of a failure). I found that there was very little performance increase by doing this, at least, that I could see or measure. My catalogue was ~3100 images in size prior to this.
One option I can certianly recommend, if you are looking to improve or optimise LR performance, is to have your catalogue on your C: drive (or location LR is installed) and have your image files on a separate physical drive.
Going further in to performance, I found that increasing the Cache size to 20GB (or at least 10% of your available space) improved image loading times noticabely. (In LR Settings).
Lightroom official stance on LR4 optimisation, well worth 10 minutes of your time: http://helpx.adobe.com/lightroom/kb/optimize-performance-lightroom.html#main_Use_optimal_settings_in_Lightroom
Tim Grey, whom I would consider a reliable source, once stated in his newsletter:
Adobe indicates there is no practical limit to catalog size from a performance perspective, and I can tell you from experience that even with 283,669 in a catalog, performance remains good.
This was a little more than one year ago and he referred to recent versions of Lightroom. Before that, apparently there had been a performance drop around 50000 images.
The appeal with a single catalog is that you can search across large volumes of images without more-or-less artificial boundaries. Say, you are looking for images of a certain subject, but don't care - or know - when you took any of them. In a monolithic catalog that is trivial, assuming proper keyword tagging. But if you split your catalog into small, pretty arbitrary, chunks with every import in a separate catalog, it will become quite laborious.
I have one catalog only most of the time. When I'm on the road with limited disk space for a longer period, I do work with a fresh catalog for that trip. But when I get home I merge it into the main one.
I tried this experiment, and found that performance was effectively unchanged with two catalogs, where one was about 1/10 the size of the other.
What really made me give the experiment up, though, was all the hidden costs to doing this:
If you want to share keyword hierarchies between the libraries, now you have to spend time exporting and importing keyword files between the libraries, because keywords are per-library.
The problem is compounded by embedded metadata when you move photos from one catalog to another, because Lightroom merges the keywords in the photo into the catalog's keyword hierarchy in the position specified in the photo. Lightroom won't readjust the photo's keyword hierarchy to match that used by the catalog.
Imagine you started with a generic
ladder > objectkeyword, then later decided you had to split the "ladder" keyword, separating out those of boat ladders (that is, stairs to us landlubbers) from regular ladders. The new keyword is
ladder > boat > vehicle. You do that to the one catalog you have with pictures taken on boats. Now you decide to move one of those photos to another catalog for some reason. Lightroom helpfully creates the new
ladderkeyword for you in the new catalog.
Some times this is exactly what you want.
Other times, not so much. What happens when a keyword moves to a new position in the keyword hierarchy instead? Say you had a
patio > house > architecturekeyword, then later took a pic of a commercial building with a patio. You decide it would be better if
patio > outdoor > place. You drag the keyword to its new position, Lightroom updates all the photos using it...all good, right? Yes, until you move one of those photos to another catalog. Then Lightroom effectively duplicates the keyword for you. If you don't then take the time to fix all the photos in the second catalog, and blindly type "patio" into the box when tagging new photos, Lightroom is likely to keep using the older keyword.
Not all Lightroom features are per-catalog, though, and sometimes this can bite you, too. For example, export plugins are shared across catalogs, including the individual export configurations.
Say you have a home and work catalog, and set up a "People" exporter for Flickr, intended to populate a "Friends and Family" album. If you then go into the "work" catalog, you'll find the "People" exporter there, too, and it will try to upload whatever photos from the catalog that match the smart collection rules.
You end up having to carefully craft Smart Collection rules that ensure the exporter only matches photos in the catalog you created it for, and ignoring the exporter in the other catalog(s).
All plugins are shared across catalogs, in fact. This can be a problem if you're a plugin developer, or are using someone else's plugin that's a little...shall we say...beta? So you try to be smart, and test the plugin with a dummy catalog first. You find a bug that screws up the catalog metadata, get distracted, open a useful-work catalog without disabling the broken plugin first, and bam, you've roached that catalog, too.
Lightroom can be asked to remember which catalog you used last and re-open that one on next launch, or to always open a particular catalog, but you will occasionally need to switch catalogs. Then you have to remember to launch the app with Alt or Option held down, then scan the list to make a decision about which one to open.
This isn't a huge burden, but it's a cost that eats into any time savings you might have gained with smaller catalogs.
Lightroom does run somewhat faster with smaller catalogs. However unless each import you do is more than a few thousand photos, I'd argue you'll see no performance benefit.
There are some good reasons for different catalogs (separating "work" and "play," for example), but I would argue that separate catalogs should not be used if performance is your only consideration.
This is an old question with answers. But it's still relevant so I wanted to clarify a bit, as LR 5 still behaves sluggish when catalogues grow large.
It doesn't matter so much how many images you have in a catalogue, it's the amount of changes you make to photos that make the catalog grow. Notably, Spot Removal and Adjustment Brush can take the size to extremes. I have one catalog with a single 32MB RAW file, but the catalog is about 800MB. This impacts any other images in that catalog, that's why I removed them all. This is by no means a standard scenario, I wanted to alter a particular photo to achieve very unique painting-like result. But at that point I've reached the limit and Lightroom pretty much crawled to a stop. Undoing some of these effects and cleaning up (by backing up) catalog did speed it up a little, but it just shows there's a limit.
So keep in mind how much editing you will be doing per catalogued folder Vs simple file count.