Operation Manual

Once your display and printer have up-to-date custom profiles, you can begin to make
accurate color adjustments to your digital images in Aperture. Aperture uses the ColorSync
CMM, or color matching method, to translate and transfer the color data from your camera
to your display and then to your printer. Although the gamuts of the devices are very
different, ColorSync knows the exact parameters of their gamuts because of their custom
profiles. The ColorSync CMM allows you to preview how the color in an image changes
when you make color adjustments in Aperture. As long as you have current profiles of
your display and printer, the printed image will closely match the image on the screen.
Calibrating Your Camera
Creating an accurate profile for your digital camera is not easy. Unless you’re using your
camera in a strictly controlled lighting situation, such as a studio, the variable lighting
conditions from one scene to another make profiling a digital camera difficult. This leaves
you with three options: shoot RAW files, painstakingly profile the camera with the best
profiling package you can afford, or use a generic profile, such as sRGB.
Shooting RAW Files Requires No Camera Profile
Whether you need to profile your camera depends on your workflow. If you shoot JPEG
files, the camera has to apply a color space to the image file. However, if you shoot RAW
files, no profiling is necessary. A RAW image file consists of bit-for-bit data captured by
the digital image sensor. When you select the RAW setting on your camera, the camera
ignores the color space settings. When you import the RAW image into Aperture,
Aperture ignores the color space settings as well.
Profiling Your Camera
Most digital cameras are set at the factory to shoot in a default color space when you
first use them, but each camera, regardless of manufacturer and model, has a unique
gamut. In order to color calibrate your camera, you need to create a new custom profile.
Color calibrating your camera requires a profiling package designed for profiling digital
cameras, a carefully constructed lighting environment dictated by the profiling package,
and the use of a color calibration target. Because each camera is unique, you must repeat
the color calibration for each camera.
Using a Generic Profile
Provided that your displays and printers are calibrated, setting your camera to shoot using
a generic profile, such as sRGB, is easier than profiling your camera. Most digital cameras
have more than one color space option available. As the image is shot, the camera converts
the image from its native color space to the generic color space you selected prior to
shooting the image. When the image file is imported into Aperture, ColorSync manages
the color in the image according to the generic color space and accurately displays it on
the screen.
862 Appendix A Calibrating Your Aperture System