louiscar I don't really know what you are looking for but I have found some processing problems myself.
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Thanks Peter, I'll look at some different software as you suggest. I use Capture NX2 and Lightroom generally. If I've got time I'll prefer Capture as it's Nikon's own software and pretty good.
Calibration was a problem with me but relatively I can look at images from others and see a difference. I can see the grey scale on the right ok althought this monitor was a pain to calibrate and I used to have a much more contrasty image which lost a few steps at the dark end.
I think I might also hard reset the camera and just to see if something in my settings might be a problem although I've tried so many settings and gone to basic raw with little or no adjustments.