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+--- Thread: Different Value Between Sample Points Vs Color Picker (/Thread-Different-Value-Between-Sample-Points-Vs-Color-Picker)
Different Value Between Sample Points Vs Color Picker - Krikor - 06-26-2019
The different value between Sample Points Vs Color Picker.
Hello, I'm not sure how to explain, but I think the image illustrious enough about my doubt.
I use the Color Picker (CP) to find a point (X,Y) of the image with a certain amount of tone desired. So I create at the same point (X,Y) a Sample Points (SP).
As the point is the same, the image is the same, the Value should be the same in the Sample Point window and in the Color Picker window, and usually has been, but ...
In the creation of points 01 and 02 indicated in the image, there was fidelity between the values of Value displayed by SP and CP, but when defining point 03, there was a discrepancy.
According to the image below, for the same position X = 576 and Y = 676 the Value at the sample point is 42%, while in the Color Picker it is 37.6%
[attachment=2963]
Maybe I'm doing something wrong, but what?
Why different values?
Thx.
RE: Different Value Between Sample Points Vs Color Picker - Ofnuts - 06-26-2019
Likely a matter of a dialog showing perceptual/gamma-corrected values while the other is using linear light. What is the image precision?
RE: Different Value Between Sample Points Vs Color Picker - Krikor - 06-26-2019
(06-26-2019, 07:50 PM)Ofnuts Wrote: Likely a matter of a dialog showing perceptual/gamma-corrected values while the other is using linear light. What is the image precision?
8 bit integer.
Perceptual gamma (sRGB)
But only the Color Picker for the coordinate (576,676) differed in the % of the Value.
Would it be possible to make the dialogue uniform in some way? So that both always show the same values for the same coordinate?
Thx Ofnuts.
RE: Different Value Between Sample Points Vs Color Picker - Krikor - 06-26-2019
- Both Sample Points and Color Piker are disabled with "Sample Merged" option.
- In the Color Picker I varied the radius of the "Sample Average" option but did not result in equal values obtained between SP and CP.
- Image in RGB mode, 8-bit Precision, Gamma Perceptual (sRGB).
Unfortunately the impression we have is that Gimp has two tools that should a priori have a same reading of the images, but for some reason each one has its own value.
Using the Radius of the Color Picker in 1, and getting the Hex reading: f2b8a1.
For this same point the Sample Points displays Hex: f1b79f
RE: Different Value Between Sample Points Vs Color Picker - Ofnuts - 06-27-2019
(06-26-2019, 11:13 PM)Krikor Wrote: Using the Radius of the Color Picker in 1, and getting the Hex reading: f2b8a1.
If the radius is 1, then the area is 2x2=4 pixels (roughly) because 1 is its radius and not its diameter, so you aren't sampling a single pixel but several. You would have to disable "Sample average" for this.