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

[DJ]

Hi laptop, gimpusers,

>> 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 lower left-hand corner or Pointer Dialog.
>> 
>> I brought up the Levels Dialog and clicked the middle eye dropper for
>> picking the gray point, and carefully relocated that same x/y
>> coordinate.
>> 
>> My question, is there another way to remember or set the gray point,
>> or remember any point for future reference/recall?  

> Have a look at Sample points dialogue.
> Norman

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,
and that you had to open it separately.

1) Does anyone know why adding a sample point might not open the
Sample Points Dialog automatically?

Second, with the sample point selected, I opened the Levels Tool. I
want to use this sample point as the "gray point". In the Levels Tool,
I clicked the "Pick gray point" eyedropper, and then went to click on
the sample points, but the only thing that happened was the cursor
changed from an eyedropper to an eyedropper+move_symbol, which means,
according to the status message at the bottom of Gimp, I can move the
point, but I can't seem to use it.

2) Now that I have a sample point (the gray point), how do I use it in
the Levels Dialog?


Thank you.

-- 
__________________________     
DJ