Reviving a dead thread here.
Colour banding leapt out of Photoshop the other day and punched me square in the nose. Problem is... I can only replicate it on my late 2010 27" iMac and not my Win7 PC at work (both have Photoshop CS5).
Is there a hardware reason why colour banding happens? I know it's not strictly part of the graphic file itself and opening the file up on another machine (or printing) should look fine but there is a level of paranoia that worries me?
Curious if it's happened to anyone else in a similar situation. Googling it (regarding the iMac in particular) reveals that it might actually be an iMac screen problem.