[Gimp-user] Picking Gray Point in a Photograph and recalling pixel points

[Sven Neumann]

Hi,

On Sun, 2009-06-07 at 13:42 -0500, DJ wrote:

> The original tutorial that I was following at
> http://digital-photography-school.com/precise-color-cast-correction-with-gray-fill-layers
> had the user add a temporary 50% Gray Layer (7f7f7f), Mode: Difference
> to find a gray point. I manually picked the point, wrote it down on a
> piece of paper, and then relocated that point in the Levels Dialog. I
> had asked the question, is there another way to remember this x/y
> location. This is where the Sample Points Dialog was suggested to
> record the location, I think, rather than writing it down on a piece
> of paper. It's a nice idea and Dialog.

Probably the easiest way to mark a point is to use two rulers. But sure,
the sample points can also be used for that.

The grey-point picker in the GIMP levels tool doesn't require you to
pick a perfectly gray point though. It is totally sufficient to pick a
point that is supposed to be some shade of gray. Basically any surface
that should be white will do it. The actual luminance is not relevant.


Sven