| Joined: | Mon Apr 2nd, 2012 |
| Location: | South Lakeland, UK |
| Posts: | 4066 |
| Status: |
Offline
|
If you look at a histogram of a clean sharp test card black and white image the histogram should show a sharply defined absolutely perfectly vertical edge to the difference between the black and the white portions of the image.
If the lines on an image of a test card are blurred then that blur will be a graduated grey.
If there is any graduated grey in an image it will show up on the histogram.
There is also a numerical display which gives a definitive reading. I just forget how that is done, will try to remember to check it out. It's on a tiny icon on the Histo panel I think.
By selecting portions of the image at say corners, edge and centre, the differences can be assessed.
____________________
Robert.