I use 2 Macs with Aperture. A Retina MacBook Pro that I use in the field, and then my desktop Mac Pro.
I maintain my "master" library on my Mac Pro and it's the final machine of record. When I'm away shooting, I will create a new Aperture library on the MacBook Pro, and work within that library. Then I come home, copy that library to my Mac Pro, and then I import the library into my main Aperture library. All my photos, adjustments, and metadata come over intact. This works great, and I've been working this way for 6 or 7 years.
Your workflow is a bit more complicated in that you want a bit more "2-way" about it. You can export projects as libraries from Aperture, then open them on a second machine, make changes, and then re-import them to your main machine if you want. This should work fine, and your adjustments/tweaks/etc., should transfer over. But you do need to be mindful.
My advice would to really only be doing major changes on photos on one of your machines at a time, and don't rely on complicated merges as while Aperture is good at this stuff, it's complicated.
It should be very easy to export a library as a project for a slideshow and use that on your second machine, if that's all you're looking to do.
I do this all the time. I have an iMac (desktop) and a MacBook Pro Retina Display.
I divide projects into two categories: completed projects and active projects.
All active project are kept on 2 TB Western Digital USB 3.0 drives. Those project are managed libraries...that means the RAW images are stored in the Aperture Project Library on the external drive. When I want to work on it on my desktop, I plug it into my USB ports on my iMac and I am up and running. When I travel, I plug it into my MacBook Pro Retina Display and I am up and running. I back up this working drive daily when I am on my desktop iMac. I have found that I might have 2 or three 2 TB passport Western Digital drive that have active projects on it. Some clients simply can not decide what they want. Each of these are regularly backed up. I have used SuperDuper for this back up process, but am moving toward using Carbon Copy Cloner.
ONCE a project is completed, I move it to my desktop computer by importing the library into my yearly master library. I then relocate the master files (now they become referenced) to an external 6 TB Thunderbolt drive into a file structure I would be happy to describe if you are interested. The yearly master library resides on an internal iMac drive. For example, I have 2011, 2012 and 2013 master libraries residing on my iMac internal drive, but all the image files are stored on a 6 TB Thunderbolt drive. The external thunderbolt drive is backed up and archived. The internal drive that holds the libaries is also backed up and archived.
I don't reuse my working drives (2 TB WD Passport drives), but save them as they are filled. In the final analysis, I have 4 copies of my RAW files
1. 2 TB Passport Western Digital Drive
2. On my primary long term iMac storage drive
3. My back up of my primary iMac storage drive
4. My archive of my backup drive of my primary iMac storage drive
The drives that serve as my backup to my working passport drives eventually get recycled as I need the backup space.
The critical aspect related to your scenario is I use my Aperture Libraries on external USB 3.0 drive that I can plug into any computer I need. At this very moment, I have three such drives plugged into my iMac. Next week when I travel to my cottage, I will take these three drives with me and work seamlessly. The BIGGEST risk is I do not have a daily back up strategy or my working files when I am traveling, but I do believe there is a long term solution to this issue as well.
This is a long winded response to say I agree with Kirby and somewhat simpler than William's solution, I think.
Please ask details, but this is a very simple problem to solve.
I would add one additional detail.
When I travel and really on the road, I do NO editing, but only importing and backing up images. My goal is to have 2 or three copies of primary images so that the primary images are protected.
When I travel to a second or third sort of permanent location, I link my MacBook Pro retina display to a Thunderbolt display at which point editing is a delight.
I would add that I manage between 30-40,000 image a year with this approach and more recently video as well but that is not quite as critical.
There are lots of ways but I think it's hard to define a best practice as even a minor difference in requirements can make one solution preferable over another.
A fast external drive for your master library that you use with both the iMac and MBO is an easy and foolproof system because there is no 'syncing' involved and you are always up to date. But it may be inconvenient from a number of perspectives, such as backup strategy, especially while travelling, and using an exernal drive is sometimes a hassle when using the notebook like this :
If you keep your master library on the iMac, for on the road slide shows and emergency edits, you can export a subset of your library into a new library and copy it to your MBP (or create a share on the MBP and export it there directly from the iMac - depends on size and wifi speed for the fastest way to copy it across). If you make any edits on the road, when you get back, you can merge this library back to your master (Import Library option) so the edits are transfered to your master library.
For new photos while travelling, you can use your exported library, but you may prefer to use a new Library. This may simplify your backup strategy for new photos, by having them seperate you can give them a higher priority for backup and possibly make use of a wider range of media (eg thumbdrives that fit in your pocket). When crossing certain borders in Asia, there is always a risk something will go missing, and the only things that are irreplaceable are my photos, so I like to have three copies. One on the computer in my backpack. One on a hard drive in my case (if I have one) and one in a thumbdrive or very small hard drive in my pocket.
Thanks for all your responses. It helps to get different perspectives.
Here is how my life is currently distributed:
Type of work done - Shoots & photo edits for e-com sites, done by my team. I dont do any hands-on work here. No images from this shoot come into Aperture. My job is to supervise, QC review & client management.
I work from my laptop when at my studio.
Type of work done - Editing of all photography work done by me i.e. Weddings, Travel, Portfolios etc. All of this work is stored in Aperture. My iMac sits at my home.
A small twist to the above scenario is that my personal time is primarily spent in editing Wedding, Travel & Portfolio images, whether I am at home or at my studio. Which means that I need to have the latest Aperture files with me irrespective of working off my MBP or iMac. for e.g. I am at the studio all day working off my MBP, spending a lot of time editing my Wedding work. In the evenings & weekends, when I am at home, I would like to continue editing the same files off my iMac.
There are two approaches I have in mind:
1) Do a daily export/import of the folder that I want to work on, from my iMac to MBP, and carry it to my studio. Work on it all day. And then do another export/import from the MBP to iMac when I come home.
2) Keep all my Aperture data (I work referenced) and Aperture library on an external drive. And work off this external drive from either my iMac or MBP.
Today I am implementing approach 1, lets see how it goes for a few days. Though I realize I spent 30-40 mins just exporting a 40GB folder. And will spend the same amount of time in the evening reimporting it into the iMac.
I dont have any specific query at the moment, but any thoughts are welcome.
Approach 1 failed miserably. I exported a wedding from my iMac to carry to my office and work off the MBP. However, Aperture in MBP refused to import it. It hung up, and also ended up corrupting ALL the 36000 images I had on it. (I have a back-up, so no worries). But it got me scared. Not sure whether this approach can work smoothly.
And I have had poor experience in working off an external drive. All my Macs randomly disconnect external drives giving me error messages saying that it was incorrectly disconnected, remember to eject it first.
Still struggling with this issue. Didnt realize owing more than one machine can turn out to be an issue rather than a solution:(
(apologies for these FB like daily updates)
How are you trying to connect to the computer and MBP. Firewire, USB 2.0 ?
Whose external drive are you using?
Have you verified with Disk Utility the external drive?
Make a backup copy of the external drive or a second backup and then rebuild the library on the external. If you have had random disconnect problems, the library may be corrupted.
Neither approach should give problems so I think you may be discovering some other issues with your system. For example, external drives randomly disconnecting is not normal behaviour. If you can resolve that issue, working off external drives should be fine for your needs.
Exporting/importing is always going to incur an overhead so for a daily solution, I think the external way is the most promissing. Just need to resolve the random disconnects. Probably best raised as a new issue in the OSX or Mac forums.
Here is what I have found works for me over the past few weeks.
While all my images reside on my iMac at home, I export libraries (that I need to work on) as a folder to an external drive and carry that with me to my office, where I work from my MBP. I continue to use the external drive even while I am at home over the next few days (by connecting to my iMac) until all images are edited and ready for delivery. Then I import the library back to my iMac. This way the iMac retains all images (RAW + Edited).
But here is a small issue that I have encountered, it'd help to get a solution:
All my images are always stored as 'Referenced'. When I export a folder as a library, it converts all my 'referenced' images to 'managed' and bundles the folder as a single library. However, when I import the library back to my master Aperture library, it should covert the images from 'managed' back to 'referenced', as that is how their original structure was. But I notice that Aperture doesnt handle the imported files this way. This results in duplication of images (the same RAW files exist as 'managed' as well as 'referenced' images) and spoils the way in which I maintain my images. Can someone help on this?
I have no problem with Aperture exporting it as 'Managed' files on my external drive. That's how I currently keep them. My problem is that when I re-import them to the iMac (which is where I originally exported them from), they still continue to be stored at 'managed', whereas I need to be 'Referenced' on it.
You misunderstand what I am saying. I always work with my library on the external when using it across two or more machines. It never ends up on my main machine until I am done with it so I don't have to export it again.
BUT when you select to export to a library, you have a choice in the export box to include or not include the original images. But if the original images are not present on the external drive, you will not be able to do any editing on them, just view them.
Again, my suggestion is use an external drive all the time with the library residing on that until such time as you are done. Whereever you have a copy of Aperture, you can work on that library by just plugging in the external drive. Once done, import it into your iMac library along with the Masters.