NSImage color shift on Snow Leopard

My app creates NSImages by compositing various other NSImages together. The original images are loaded from files using [NSBitmapImageRep imageRepWithContentsOfFile:]. The final image is then displayed on the screen.

A few 10.6 customers have reported that the image they see (sometimes) has shifted colors. Specifically, all of the bright colors look dull and washed out. Blu开发者_如何学Pythone seems to be shifted in the purple direction.

I know this must have something to do with NSImage or NSBitmapImageRep's handling of colorspaces, gamma, or ColorSync? I know there were gamma changes in Snow Leopard.

Does anyone know where I should start? It's hard to troubleshoot because I can't reproduce the problem, but I can see form the customers' screenshots that the colors aren't right.

Anyone seen this before?

Blue seems to be shifted in the purple direction.

This is a bug in Snow Leopard. Anything approximately blue drawn in Generic RGB gets color-incorrected to approximately purple. You can even see this in the menu highlights.

http://boredzo.org/screenshots/SnowLeopard-PurpleIsTheNewBlue-MenuSelections.png http://boredzo.org/screenshots/SnowLeopard-PurpleIsTheNewBlue-MenuSelections.png

(If you don't believe that that's purple, break out DigitalColor Meter. It's most purple near the bottom of the gradient.)

I filed a bug report: x-radar://problem/7542845. I included plenty of photographic and videographic evidence, which you can see in the OpenRadar copy. I invite you to file a duplicate.

It doesn't happen for everybody; if the above image looks fine for you, watch the video, which has the red-shift baked in from the video conversion and shows the difference in DCM.

Snow Leopard changed the default gamma: http://support.apple.com/kb/HT3712