ColorSync

Color Profile:

iPhoto uses ColorSync profiles, which provide an easy way to ensure accurate color in your images from the time you import them until you print or display them.
If a photo does not already have a color profile embedded, iPhoto assigns one so the photo can be viewed properly in iPhoto.

You may want to change the color profile settings if you:

  • Plan to use advanced editing tools outside iPhoto
  • Import photos from your hard disk and decide to have iPhoto point to your original files (instead of copying them)
  • Know that your photo has a color profile already embedded

To set or change color profile options:

  • Choose iPhoto > Preferences.
  • Click Advanced.
  • Select or deselect “Copy items to the iPhoto Library.”
  • Deselecting this option means that iPhoto will not duplicate photos when importing them into the application, but will leave them in their original locations on your computer. When you edit these images in iPhoto, however, the edited versions will be saved in the iPhoto library. Your original files remain untouched.

If you selected “Copy items,” do one of the following:

  • Select “Embed ColorSync profile” to assign a color profile.
  • This is usually “cameraRGB,” an Apple-specific version of the commonly used sRGB, which allows image colors to map more closely to Apple monitors. If your image file settings specify the use of Adobe RGB, iPhoto assigns that profile.
  • Deselect “Embed ColorSync profile” if you want to import the photo in its current state, and do not want to add a ColorSync profile to the image.

Colorsync options:

iPhoto 6 and later versions include an option to embed a ColorSync profile when importing a photo. To access this feature, choose iPhoto > Preferences, and click the Advanced tab.

Key points of the feature:

  • You can only select this option if the option to copy photos to the iPhoto Library is also turned on.
  • If an image already contains an embedded profile, iPhoto will not overwrite it.
  • iPhoto does not recompress the image when embedding the profile. Since there is no image or speed degradation, leaving this option on all the time is recommended.
  • If the image contains no profile and this option is selected, IPhoto will normally embed a Camera RGB profile image.
  • IPhoto will always attempt to use the image’s embedded ColorSync profile when displaying an image. If no profile is embedded i the image, iPhoto may use the CameraRGB profile to display the image to approximate a simplified color space.
  • Even if the option to embed a profile on import is not selected, iPhoto will embed a profile when you edit an image that lacks a profile. In this context, editing includes rotation of the photo.

Exceptions to CameraRGB:

  • If the photo is an AdobeRGB colorspace JPEG and contains EXIF2.2 data, and you are using Mac OS X 10.4.3 or later, iPhoto will embed an AdobeRGB1998 profile.
  • If the image is an AdobeRGB colorspace JPEG and contains EXIF 2.2.1 or later, iPhoto constructs a profile programmatically from information in the EXIF.
  • If the image is a RAW file, the profile will be created programatically based on information contained within the RAW file. The profile will be created at the time of conversion to JPEG or TIFF and embedded in the resulting JPEG or TIFF file (the RAW is left alone). Conversion happens when you edit or export a RAW image in iPhoto.
  • If the image contains no EXIF data to aid in creation of a profile, iPhoto may use the current display profile to render the image for viewing. If you edit the photo, this profile will be embedded in the edited copy of the image.

Alternative methods:

If you want greater control over which profile is embedded, see “Grayscale images appear inverted” for information about AppleScript items included with some versions of Mac OS X, which you can use to change the profile.
Alternatively, you can set the external editor in iPhoto to ColorSync Utility, Preview, or another application which will allow you to modify the profile.