Page 1 of 1
Posted: Sun Nov 09, 2008 5:47 pm
by ggroess
Mike,
The Shadow thresholding does not accurately reflect the grid controls on the image. See screen shots attached.
Shot 1 is where the black specks show up on the image. Showing the histogram and the placement of the threshold. Image 2 is the result if you place the threshold where the specks show up....
Greg
Posted: Mon Nov 10, 2008 2:28 am
by -default
Greg, I think it's probably working correctly - or I'm misunderstanding the problem, which is also likely.
I opened your second image in CM, and clicked on the edge of the Lab curve, and the preview looks about the same - black dots. Screenshot included.
Posted: Mon Nov 10, 2008 2:34 am
by -default
Rereading your post, I'm thinking I totally misunderstood what you were getting at. Is it that the histogram doesn't seem to match up with the darkest parts of the image?
Posted: Mon Nov 10, 2008 4:32 am
by ggroess
No, it is that the black threshold is over doing the correction.
I have to back out to the edge of the histogram to get an acceptable shadow value.
If I slide the shadow edge control over to the left until I see the dots, (thresholding)... the correction is too far gone for shadow details. When I bring the threshold over to the edge of the histogram (Approx. Value) I can get a good shadow setting but the black dots are not showing on the screen correctly.
It was confusing at first because I was going for a quick and dirty correction for proofing this image. I just about dropped a jaw bone when I saw what the thresholding did.
These all seem to be pointing at the curve control don't they??
Do I have a bad version of it??
Greg
Posted: Tue Nov 11, 2008 12:36 am
by -default
Hi Greg,
I'm staring a hole in this, and after a couple of images, I still don't see a bug. It seems to me there just a small number of pixels that show up on the preview image as black specks, with the bulk of the dark histogram being the darker areas of the sweater.
Can you get a similar problem working with a black-white gradient? Or maybe I just have a blind spot to your explanation, in which case my apologies - I'm trying!
Posted: Tue Nov 11, 2008 4:16 am
by ggroess
Let me kick a few other images around maybe this one is really weird...
I'll test a few and see if this is still an issue...
Greg