Well after further testing on a variety of images, I am satisfied that what I wrote above (in the post that includes Bill Atkinson's Test Page) is essentially correct. After running an image that's in a wide color space (e.g., prophoto or Adobe RGB) through piccure+ version 3, any colors that are outside of sRGB will be clipped. This phenomenon is easily visible on a wide gamut monitor. If you work only with a standard gamut monitor, you won't see the changes because those colors aren't displayed on your monitor to begin with. They might have been printed by your printer, but after processing with piccure+ v.3, they won't be because they have been replaced by colors that are within sRGB. On the positive side, if you don't mind this behavior, piccure+ does a good job of sharpening most images.