Metadata is the key to a successful image management workflow. Metadata falls into 3 main categories: camera-applied, image properties, and user-applied.

Camera-applied metadata

When you take a picture with a digital camera it attaches quite a bit of info to the image. You get info like shot data (aperture, shutter speed, ISO, focal length, lens type) and camera info (make, model, and serial number). There isn't much you can do about camera-applied metadata except adjust an image's time - for when you cross time zone lines and forget to adjust the camera's time.

Image properties

Image properties simply describe the image file itself and not it's contents: dimensions, format, color bit depth, file size, etc. Like camera-applied metadata, image properties aren't user editable (OK, you can change them by changing the image...). This metadata can be useful if you are looking for panoramic images (for example where W:H is 10:3 for example), 16-bit TIFFs (like images externally edited in Photoshop), etc. Aperture doesn't make it as easy as it could to use this sort of metadata in searches.

User-applied metadata

This is the real meat and potatoes of image metadata tagging. The mere action of filing images into Projects and Albums is tagging images with metadata. In Aperture, even importing an image adds some special metadata: Import Group. You can use Import Group in searches and smart albums.

There are a few metadata fields that every image can/should have:
  • Sub-Location
  • City
  • Province/State
  • Country

Sometimes the City can't be easily determined, but it is rare that I don't put something in Sub-Location, even if it is "Interstate 70"

Here is how I recommend using Aperture's metadata fields:
Location Tags
Sub-Location The place that the image was taken 1600 Pennsylvania Ave
Yosemite NP
Interstate 70
City The city where the photo was taken Ligonier
Pittsburgh
Province/State The State where the photo was taken PA
Pennsylvania
Country The country where the photo was taken USA
United States
Rights Tags
Byline Who took the picture Brett T Gross
Byline Title Title of the creator Photographer-at-large
Credit How the author should be credited
At least that's how I use it		 Brett T Gross
Contact How the author should be contacted
At least that's how I use it		 email:brettgross at mac dot com
phone:724 555-1212
Copyright Notice The copyright of the image
I've been told it is important to add the year and the word "Copyright"		 Copyright © 2005 Brett T Gross. All rights reserved.
Description Tags
Object Name The name of the photograph Sunset over Yosemite Valley
Headline A short description Sunset
Caption A full description of the image
I use this in photo books		 Trees reflected in Lake Irene, Rocky Mountain NP, Colorado
Rights Tags
Byline

Tags I don't use... and maybe why I don't use them...
Category
Supplimental Categories		 I use keywords for this. Keywords are very multipurpose
Content Location Name I'm not sure how I would use this tag as I already use Sub-Location for this
Content Location Code
Country Code
Editorial Update
Object Attribute Reference
Language Identifier
Object Cycle
Object Type Reference
Originating Program
Program Version
Reference Service
Subject Reference
Urgency
Writer/Editor		 I'm sure these have their uses- but not for me
Date Created
Digital Creation Date
Digital Creation Time		 Aperture is strange about the formatting of this field. I use the EXIF tags for this.
It would be helpful if you could arbitrarily change the date/time instead of just time zone (Lightroom can do this...)
Edit Status I would use this tag if you could determine if an image had been edited via AppleScript
I'm looking into a workaround
Original Transmission Reference I've tried to use this for a unique serial number. For various technical reasons I stopped doing that
Source I've tried using this instead of the EXIF source device but stuck with the EXIF tags
Date Created