#OCR IMAGETYPE SHOULD BE GRAY OR RGB PATCH#

Likely a white point at 5500k-6500k would be better and we should also make sure that ambient light (idealy a calibrated light such as Just) and wall color (white, dirty white ?) are in the range of acceptable grayness.

#OCR IMAGETYPE SHOULD BE GRAY OR RGB PATCH#

My 5000k for the white point is a bit warm, and I see the brown patch more colored than the blue one. I lowered the saturation until I had the feeling both were gray, I reached 4% and 5% saturation in the HSL space. With a calibrated Eizo CG303w (120cd/m2 5000k 2.2), I have the feeling that the one on the left tend to the red and the one one right on the blue. In the two samples provided I measured (with Photoshop eyedropper):Ġ 10% 49% and 216 12% 51% which differs a bit from what you claimed, maybe due to a color profile being dropped in the publication process. Grayness can be seen as a distance S (saturation), which is 0.0 if pure gray, and 1.0 if it is the farthest from gray. HSL is the best color space to represent grayness. I guess the questioner expects something that could help his program make the same decision than a perfect colorimeter would do when it reads the same RGB outputted by a faultless sRGB screen with no disturbing extra lights. This is of course a lie if the screen isn't color calibrated.ĪDD due comments: The questioner very likely believes his program doesn't get fooled by anything else what it has seen, it can concentrate to a single RGB combination at a time. Those systems are developed to be more linear in predicting what's seen.

You should instead of it convert your RGB values to LCH system and extract C (=chroma) or to CIELAB system (=Lab in Photoshop) and calculate sqrt(a^2+b^2).

RGB or actually the saturation in its polar coordinate equivalents is highly nonlinear when one tries to use it as a measure for 'how near grey this RGB color seems to be when watched on the screen' It doesn't at all take into the account human color vision, it's purely for controlling the screen electronics.

Ocr imagetype should be gray or rgb