Maybe this is normal and I simply don't understand what IR really is, but I had a 2012 iMac delivered November and just today (May 2013) showed first sign of image retention. So I did a screen grab and the resulting image shows nothing unusual. Would I have to take a photo of the screen to see it captured electronically? Does this mean that pixels are not affected, but possibly some image memory being reflected onto the outer panel? (this doesn't even seem plausible) I'm confused and also wondering if I should call Apple about this. The image was strong enough to see clearly without question.