Raised by the port and independently reproduced here before being adopted, since
adopting their claims unchecked has misfired twice this session.
Binning matched pixels by render level rather than fitting a scalar, the implied
exponent falls monotonically and crosses 1.0:
render 16 23 31 39 47 64
port (all) 1.26 1.18 1.10 1.03 0.93 0.85
mine (flat) 1.303 1.347 1.128 0.912 0.935 1.003
Below the crossing the capture is darker than the render, which is what the page
measured; above it the capture is brighter. A single exponent cannot express a
curve that crosses unity, so the model is valid only in the darks -- which is
exactly the reach the page already stated. The reach line was not a hedge, it was
the finding.
Where the two disagree is recorded and not resolved: the crossing is about 44 by
their binning and 35 to 40 by mine, and the darks read 1.18-1.26 theirs,
1.30-1.35 mine, 1.49 for the page s original patch fit. Three estimators on three
populations, all agreeing on direction and on gamma above 1 in the darks.
A confound in my own reproduction is stated rather than left implicit: whole-image
correlation is only 0.594 because the committed capture and the default render
differ in focus state, which the port measured as 74.1 percent of differing
pixels. My bins include that mismatch, so they are not a clean second opinion.
And a 1280x720 render against a 1279x675 capture needs a resample, which is why
the fit is restricted to flat-neighbourhood pixels.
METHOD gains the general form: a stated reach is a boundary rather than a hedge,
and the fix was printing the curve instead of a scalar, because a scalar hides
its own domain.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QsEPXWVaEpyfudtR6re1Pd
2a7ac9f859