I asked about this here https://www.nikoncafe.com/vforums/showthread.php?t=236378 and never got around to responding to Mike's suggestion to post a 100 percent crop, so I'm doing that now with a different photo: Subscribe to see EXIF info for this image (if available) This is a 100 percent crop of a .NEF which I have opened in NX2, souped up a little with color control points (one of which is just to the left of the cloud in this crop) and then saved as a .jpg. No resizing other than the crop, and no sharpening. To me this seems regularly irregular (very small globs) and therefore likely to be noise. Here's the same crop, converted to B&W. In this one I think I see little squares or rectangles rather than very small globs, which is why I wonder if it's a conversion artifact: View attachment 388245 I have seen this same type of thing with previous B&W conversions of .mrw files taken with my Konica-Minolta A2. I used a polarizer in the image I'm putting up here and I also used a polarizer on all of the unsatisfactory B&W conversions with my K-M A2.