sylpheed-port ran the signed-edge discriminator I proposed but could not execute --
it needs their render beside the capture. Recorded as their measurement, with their
tool and commit.
Controls against deliberately damaged copies of their own render: a known +1 px
shift reads back as +0.938 px, a known blur as r -0.896 on the laplacian, neither
leaking into the other's channel. The menu against the capture gives -0.010 px
horizontal, -0.009 px vertical, laplacian r +0.103 -- and the weak blur term is the
opposite sign to the blur control.
So global misregistration and blur are both excluded, and of the three candidates I
named the misplaced soft element is the only one left.
Reach is the whole reach: a whole-frame fit excludes a global translation, not a
local one, since one misplaced element is a small share of 38752 edge pixels. The
next test is local and needs the residual map, which is theirs.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wuu56cE8vJGTBtn1ppsk8v
1e93b6a2e2