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iPhoto 4.x color display difference compared to other applications

iPhoto 4.x color display difference compared to other applications

David Duke reader reports a problematic color shift in iPhoto 4.0:

"iPhoto displays photos, having embedded sRGB profiles, with a distinct color shift (approximately +5 to +7%R,-2 to -4%G, +3 to +5%B) compared to viewing the same image, side by side, in other ColorSync aware applications like Preview, PhotoStickies or as a desktop image from System Preferences. I became aware of this problem trying to solve the "smoothing" iPhoto 4 now does to images in Edit & Organize modes, and had selected Preview as an alternate viewer to use when double clicking an image in iPhoto.

"Visually this means a photo of a sunset looks yellow gold viewed in Preview and rose pink viewed in iPhoto. The color shift is not as noticeable for all images and depends on the color makeup of the photo. Some photos look completely different - with others the color shift is not obvious.

"Interestingly when I change image thumbnail size in iPhoto's Organize mode the color shift is NOT present for smallish thumbnails, under approximately 250 pixels in width, about 90% on the image size slider. Increasing thumbnail size beyond this size, or viewing them in Edit mode, I see the color shift snap in as iPhoto does its smoothing."

We previously reported a problem in iPhoto 4.0 where some users' images become blurry - with an exaggerated smoothing effect - when in "Edit" mode.

The primary pitfall of that issue is users are unable to distinguish between a naturally blurry photo due to camera problems, or an artificially blurry image due to iPhoto. When images are exported, they do not exhibit the blurriness, indicating that this is strictly a problem with iPhoto's rendering and smoothing scheme. However, a handful of readers have reported similar behavior in Apple's Preview.app. Compounding the issue in this case is the fact that there is no way to turn of anti-aliasing in Preview.app under Mac OS X 10.3.x (Panther).

Duke continues "I could duplicate the color shift problem on a 14" 700MHz G3 iBook running OS X 10.2.6 and iPhoto 2. On that system iPhoto displays images with an obvious color shift compared to the image viewed in Preview. I discovered I could fix the problem by changing ColorSync's default RGB (for documents with no embedded ICC profile - not an intuitive fix as the images have embedded ICC profiles) from "Generic RGB" to "sRGB", the same profile as embedded in all the images.

"The best workaround I have is to keep thumbnails small in iPhoto Organize mode and view images at larger size in Preview when color balance is important. I am assuming the fault lies with iPhoto given that iPhoto is the 'odd one out' compared to other means of viewing images with ColorSync matching in OS X 10.3."

If you are experiencing a similar problem, please drop us a line at late-breakers@macfixit.com.

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