sensorWhite hung its nine counts of window off the plane's largest sample. A
hot pixel sits hundreds of counts above the level the sensor stops at, so on a
frame that carries one the window held the stray alone, found no pile in it, and
handed the develop the factor two instead of the frame's own level.
Measured on a Panasonic DMC-LX10 RW2: one sample at 15993 and one at 14665 over
a pile of 9,594,544 at 13855. The frame's level is 1.75x the fall-back, so the
develop opened 0.81 of a stop bright, clipped the sky the sensor had held to
flat, and the fit to the camera's preview could only pull the exposure back
after the highlight detail was gone. Against the camera's own JPEG of the shot,
mean |dL| 23.48 and dRGB +8.57,+0.90,+4.90 became 19.14 and +5.32,+1.89,+2.04,
and the level itself 7908 (gain 8.2872) became 13874 (gain 4.7236) against the
13855 the plane piled at — 0.14%, 0.002 of a stop.
The level is now the highest count the plane piled at, off a whole-plane
histogram: `floor` counts is a pile, and the same cliff rule as before still has
to hold over the count below it, so a smooth bright sky is left alone and a
frame that has not clipped still falls back on the factor two.
The same stray was in four of the ten bodies to hand. A Nikon _GDN0447.NEF read
the fall-back 8190 where its plane piles at 13806 (gain 8.0018 -> 4.6022, 0.79
of a stop), a Fujifilm RAF 29696 where the documented level is 30993, and a Sony
ARW 31742 against the 2.002x the body's ratio was measured at. Six were
untouched, and a Canon CR2 develops byte-identical through the change — the
window moves only on a frame whose largest sample is not its highest pile.
scripts/white-level-check.mjs keeps the LX10 shape: a plane piled at 30995 with
a stray above it has to answer 30995.
3dtours
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