I’m having problems with my color picker in photoshop CS5
Image 1: I select the black [ish] bar. Color picker returns gray.
Image 2: I select the white [ish] background below the black bar, color picker returns lighter gray.
Now I thought the color picker was using grayscale, so to test, I did the same with blue.
Image 3: I select the blue, color picker returns wrong blue.
Image 4: I select the blue color one pixel higher than in image 3, color picker returns an even lighter blue. It’s still the wrong blue, and the blue in image 3 and 4 is a solid color.
Note: there are no layer styles present!
Its because the colour picker is sampling a larger area than one pixel, and is mixing the colours.
To fix this, when the eye dropper is selected, change the sample size at the top to Point Sample
Source : Link , Question Author : AlexMorley-Finch , Answer Author : JohnB