Just curious on how hot a highlight needs to be to have the highlight clipping indicator to turn on (red) any idea what the RGB values need to be? Same question for the shadows.
This could be related to the issues I have raised in a couple of threads but this one in particular http://forums.adobe.com/message/4558412#4558412
If any channel is clipping (hitting a max effective 255) the highlight or shadows clipping preview in the image will turn on.
In the histogram window, you can see an indication of what channel or channels are clipping.
Red in the small triangle indicates it's the red channel, green would be green and blue would be blue channel clipping. If you see yellow it means both the red & green are clipped, magenta showing means red and blue are clipped and cyan indicates bleu and green clipped.
Jeff, thanks for the info, as this maybe a clue to the issue seen with clipping display in ACR; especially highlight clipping. In some of my test images I see the clipping indicator on for values lower than 255 (each channel) even at 100% magnification, which Eric thought was a rendering problem at magnifications less than 100%.
At this time I do use the histogram in ACR and the sampling dropper rather than rely on the clipping indicators as the display is not accurate, but at least it gives somewhat of a visual of potentially problem areas within an image, where I need to tame a highlight or open up a shadow area.