If you have been using Aperture for more than a little while, especially on a laptop you may be struggling with storage space issues. Referenced masters to the rescue - sort of. For the readers not familiar with referenced masters a brief review is in order. With Aperture there are two options for storing the image files that you import. Option one - the default - is called managed masters. Using managed masters Aperture copies your precious original image files into it's mysterious secret abyss never to be seen or heard from again (according to some people). In reality they just get copied as regular old files, into regular old folders, inside a special folder with a flag that doesn't let you so easily navigate into it - in other words your Aperture library. People using laptops or with huge libraries and smallish hard drives this can become a constraint sooner rather than later. Enter option two - referenced masters - using referenced masters Aperture allows you to store the files anywhere you want, on more than one hard drive, on externals, on DVD's (yuck!) wherever. You can choose the location of your master images as you import them or later down the road. In the Aperture import window you have three options to manage storage of your master images as you import them. In the Aperture library (managed masters), in the current location (referenced), or somewhere else (referenced but Aperture moves them to the location for you). The way that you deal with this down the road after importing is using File->relocate master… This function allows you to move managed masters out of the library to the location of your choice or to move referenced masters from one place to another. Aperture allows you to bring them back into the library as managed masters as will with File->Consolidate master… There is one other Aperture funciton that screws around with master image location, I'll cover this later as it deserves a it's own discussion, that function is - File->Manage referenced files. The common thread with all of these functions under the File menu is that you must select the images that you want to manipulate in the browser window before using the functions, I know that seems obvious but I see a lot of people get tripped up and confused with this one tiny little thing when trying to change over from 100% managed masters to referenced masters.
Okay, enough of the review, so where does this leave us? If you are feeling a little clostrophobic on your current Aperture machine you can easily move some or all of your image masters to an external drive using the functions just discussed. After doing so you will notice a little badge on your image thumbnails that indicate that the image is using a referenced masters. Aperture functionality will be idendtical right up until you unplug the external drive. When you do unplug the external drive that contains some or all of your master images a different little badge indicator will show up on the image thumbnails that have masters on that drive showing that the master is "offline". When a master image is offline there are a number of things that you cannot do in Aperture with that images but there is also a surprising number of things that you can continue to do even without the master images. The usefulness of what you can do will somewhat vary depending on the size of the previews that you chose to generate or if previews exist at all. You can set up preview size in the Aperture menu under preferences. I personally use HD sized previews (fit within 1920x1920) so that all of my previews are at full resolution on my presentation device of choice - HD flat panels and projectors. So part of moving to referenced masters is learning how to manage your preview images and fine tuning this as well.
Here is a succinct list of things you can and cannot do with "offline" masters:
- Use any of the adjustment controls - they will all be greyed out. Surpisingly you can see the adjustments made and even lift/stamp them to other images that are either on-line or managed as the adjustments are merely metadata.
- Use any of the export functions.
- Use any plugins
- Use the email from Aperture (kind of stupid if you have previews)
- Print any images that are offline from Aperture
- Use Aperture slideshows as long as you have previews.
- See and manipulate all image metadata including EXIF
- Do anything you want to the organization of the Aperture library.
- Use all of the keywording functions, so that you can someday catch up with the boring metadata stuff while you are on a plane and can't play around for the 1000th time tweaking the contrast on that one image.
- Use the Aperture JPG previews in all of the other OSX applications with the image browser. Pretty cool.