COLOR TEMP's swatch was Tanner Helland's blackbody fit, so it painted the
colour of the LIGHT the number names: 2500K came out orange #ff9f46 while the
engine cooled the frame on the same knob. Read off the render of a neutral
128-grey (mean of the painted preview, CCT via McCamy), the two ran opposite
ways at every stop:
K old swatch swatch CCT picture mean picture CCT
2500 #ff9f46 2384K 115,135,204 47691K (blue)
3200 #ffb87b 3096K 128,141,171 11246K
4000 #ffcea6 3931K 135,141,156 8203K
5500 #ffedde 5414K 144,139,143 6479K (unity)
6500 #fffefa 6322K 148,138,139 6029K
7500 #e6ebff 7730K 149,138,132 5555K
10000 #cadaff 10024K 153,138,128 5180K (warm)
So the number is a Kelvin of the scene's light — which is exactly why the
engine warms the picture as K rises — and the swatch was the one thing on the
ruler that disagreed with the ruler. It is now painted from kelvinToRGB
itself, the same gains the render puts on every pixel, on a mid grey, so the
band under the knob can never drift from the frame above it. kelvinToHex goes
away with it: one Kelvin->colour mapping in the app, not two.
Measured after: the swatch's R-B tracks the render's own cast at every stop
(-82 vs -89.8 at 2500K, +23 vs +24.0 at 10000K), 5500K is flat #808080 — the
engine's unity point — and 3200K sits cool / 7500K warm either side of it.
temp-swatch-test.cjs (scratchpad): 33 PASS / 0 FAIL.
3dtours
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