diff --git a/docs/port/splash-animation-fixed.md b/docs/port/splash-animation-fixed.md
index e5110c97..7614f934 100644
--- a/docs/port/splash-animation-fixed.md
+++ b/docs/port/splash-animation-fixed.md
@@ -67,8 +67,94 @@ misreading it.
 * That it **looks** right. Three instruments have now agreed with a picture a
   human called wrong, and the fourth agreeing does not change the standing of
   the fifth. A play-test is the check.
-* Anything about the **developer** splash's three logo/companion pairs. One
-  element, one screen.
+* ~~Anything about the **developer** splash's three logo/companion pairs. One
+  element, one screen.~~ ✅ **Closed below, and the developer splash turned out to
+  be the far better test.**
 * The **absolute** alpha. The shape matches; whether the port's alpha equals the
   game's at a given unit is `verify-capture`'s question, and it answers 0.01 %
   at the settled pose only.
+
+
+---
+
+# ✅ The developer splash: three elements, TWO declared shapes, on one screen
+
+The publisher check above had a structural weakness I named at the time: one
+element, one screen, one shape. If the port applied *some* single ramp to
+everything, that check would pass.
+
+**The developer splash cannot be fooled that way, because it declares two
+different shapes at once:**
+
+| element | declared alpha | middle segment |
+|---|---|---|
+| `palogo_gamearts_eff` | `0:0 15:255 30:255 45:0` | **flat** |
+| `palogo_seta_eff` | `0:0 15:255 30:255 45:0` | **flat** |
+| `palogo_anima_eff` | `0:0 15:255 30:212 45:0` | **decays 17 %** |
+
+Same screen, same frames, same clock, same code path. The two flat elements are
+the control for the one that is not — no second run, no second renderer, and
+nothing for a phase or rate error to hide behind, because any such error hits all
+three identically.
+
+## Pre-registered, before the film was read
+
+> In units 15→30, `gamearts` and `seta` hold flat while `anima` falls gently.
+> All three fall steeply 30→45.
+
+## Measured, off a real filmed boot
+
+Companion-only strips (each companion's rectangle minus the logo sitting inside
+it), mean luma, `--film-interval=0.03`:
+
+```
+segment     units 16-29  units 31-44
+gamearts       +0.00000     -0.00101
+seta           +0.00000     -0.00151
+anima          -0.00001     -0.00003
+```
+
+**The two flat ones are flat to five decimals. The decaying one decays.** And all
+three fall over 31–44, so the flatness is not a dead element.
+
+## The quantitative version, and the falsification arm
+
+Each trace normalised by a **single solved gain** — one scalar per element, not a
+per-point fit — against the declared curve, over the whole `t=0..45` ramp:
+
+| element | fitted against | max err | rms err |
+|---|---|---|---|
+| `gamearts` | **its own (flat)** | **0.49 %** | 0.23 % |
+| `seta` | **its own (flat)** | **0.50 %** | 0.27 % |
+| `anima` | **its own (decay)** | **2.18 %** | 1.19 % |
+| `gamearts` | anima's decay | 8.32 % | 4.80 % |
+| `seta` | anima's decay | 8.08 % | 4.86 % |
+| `anima` | flat | 8.82 % | 4.94 % |
+
+**Both directions.** Every element fits its own declared shape 4–17× better than
+it fits the other one available on the same screen. A port that drew one ramp for
+all three would sit at ~8 % on at least one row; none does.
+
+`anima`'s 2.18 % is the loosest row and the reason is its signal: its
+companion-only strip means ~0.0005 against gamearts's ~0.015, thirty times
+dimmer, so its noise floor is thirty times higher in these units. It still
+separates from the wrong curve by 4×.
+
+## What this adds over the publisher check
+
+The publisher check established that the ramp has the declared *breakpoints and
+slope ratios*. This establishes that the ramp is **per-element** — that the port
+reads each element's own keyframes rather than applying a screen-wide curve. That
+is a different failure mode, and it is the one that would have survived the
+publisher check unnoticed.
+
+## What it still does not establish
+
+* That it **looks** right. This is instrument five. The standing of a human's
+  eyes is unchanged by it.
+* The **absolute** alpha, for the same reason as above — a solved gain is
+  deliberately scale-free, so this is a shape result and says nothing about
+  whether the port's alpha equals the game's at a given unit.
+* Anything about the **logo** elements. Both checks measure the pre-blurred
+  *companions*, because those are the strips that can be isolated from the sharp
+  logo underneath them.