Excessive Use of Unsharp Masking

In the following sets of images, the same enhancements were made to the two original images (A). First, A was stretched to create B, then unsharp masking was done to create C and D, with a greater amount of unsharp masking done to D. By the time we reach D, unsharp masking is clearly becoming excessive -- a few stars in the M51 image have dark centers; Einstein's face is severely distorted.

M51

Albert Einstein

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