On 2010-04-05 11:27 , Jack Davis wrote:
I'll offer mine the nebulous term by saying that if at least some surface areas are rendered featureless by virtue of being too bright, I'd consider those areas "blown out." Many images can tolerate a certain amount of this condition, but it's amount is the criteria and varies with each viewer. Said areas must, of course, contain some available mask detail which defines the surface. IOW, I'm not talking about an absolute ball of glare wherein no detail is discernible.
in digital signal processing "blown out" is commonly called clipping -- parts of the signal are too strong to fit within the dynamic range of the analog-to-digital conversion process; whether it is a matter of the sensor's capacity or of what is done with the signal from the sensor, it still comes down to the fact that with digital signals, there is no way to "turn the volume to 11"
there are some subtleties for digital images, since there are red green and blue "channels" (to use Photoshop lingo), one channel may be blown out, or clipped, while the others still have detail; in such cases the resulting image may still be quite usable
the same problem occurs at the other end of the dynamic range, loss of shadow detail when the image content is "100% black"
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