I was following this tutorial.
http://digital-photography-school.com/precise-color-cast-correction-with-gray-fill-layers
I added a 50% Gray Layer (7f7f7f), Mode: Difference. I picked a point
that was black, referencing the Pointer Dialog, and jotted down the
x/y coordinate found in the
On Fri, 2009-06-05 at 12:24 +0100, laptop wrote:
I was following this tutorial.
http://digital-photography-school.com/precise-color-cast-correction-with-gray-fill-layers
I added a 50% Gray Layer (7f7f7f), Mode: Difference. I picked a point
that was black, referencing the Pointer Dialog
snip
Have a look at Sample points dialogue.
This looks like it might be it :-)
First, I was able to select a sample point per the instructions in
the documentation (drag a ruler w/the ctrl key down), but the Sample
Points Dialog did not come up. The documentation said it might not,
snip
Why would you want to use a sample point for the gray point in the
Levels tool? Just click on the Pick gray point eyedropper in the
Levels tools and then click on the spot in the image that you want to
select as the gray point. This will do what Norman described, just
completely
I think the difficulty is how to decide where the mid-grey point is.
Once decided upon then action is easy.
I thought the tutorial might have had the answer to that by using the
50% gray layer with Mode: Difference.
The Grokking the GIMP book uses modes in ways that I haven't seen
elsewhere. Most items I have read just say experiment with modes and
you'll come up with interesting effects. But Grokking actually gives
some practical examples, like using Multiple to create shadows, Screen
to create
