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The maximum value for a pure white using 16 bit/channel image is about 32000 in PhotoShop CS. The maximum value for a 16 bit number is 2^16 or 65536 and if we start the scale with zero rather than 1 then the maximum value is 65535. So why is the maximum values of R, G, B limited to something over 32000 in CS?
The defined range of values of L, a, and b in the CIELAB system is 0 to 100 for L; -127 to +127 for a and for b. Why does the color picker give values for L as high as 32000 and for a and b values such as -5200 and +5000?
I scanned an IT8.7/2 target with 16 bits/channel and then repeated that for 8 bits/channel. I selected a the most saturated red on the chart, square L17, and the color picker on the 8 bits/channel scan gave RGB values of 163, 0, 5. The color picker on the 16 bits/channel gave values of 15407, 3967, 2267 which is certainly not a saturated red. I then let CS convert the 16 bits/channel image to 8 bits/channel and used the color picker on this coverted image, same square, and got values of 124, 30, 18. Now I’m looking at two red squares on two charts tha seem identical to me and I see huge differences in the color picker’s description of those squares. What’s happening? I suspect CS has 16 bit problems.
The defined range of values of L, a, and b in the CIELAB system is 0 to 100 for L; -127 to +127 for a and for b. Why does the color picker give values for L as high as 32000 and for a and b values such as -5200 and +5000?
I scanned an IT8.7/2 target with 16 bits/channel and then repeated that for 8 bits/channel. I selected a the most saturated red on the chart, square L17, and the color picker on the 8 bits/channel scan gave RGB values of 163, 0, 5. The color picker on the 16 bits/channel gave values of 15407, 3967, 2267 which is certainly not a saturated red. I then let CS convert the 16 bits/channel image to 8 bits/channel and used the color picker on this coverted image, same square, and got values of 124, 30, 18. Now I’m looking at two red squares on two charts tha seem identical to me and I see huge differences in the color picker’s description of those squares. What’s happening? I suspect CS has 16 bit problems.
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