cri: integrate on the 1 nm CMFs — agreement with colour-science to 0.03

John asked whether the values could gain a decimal. Investigation:
- TM-30 already agreed to 0.002 (the loose tolerance was hiding it)
- CRI's F-series residual (-0.03..-0.08) was hunted through three
  hypotheses: CCT method (exonerated -- Robertson vs our exact locus
  differ < 1 K), boundary extrapolation (exonerated -- moves 0.001),
  integration practice (CONFIRMED -- the 5 nm abridged Riemann sum vs
  1 nm-practice integration accounts for 3-5x of it)
- fix: cri() integrates on the CIE-normative 1 nm CMFs (what we shipped
  them for: F-series line+phosphor spectra ARE the spiky case) with a
  1 nm Planckian reference. Residual now Ra <= 0.027, Rf/Rg <= 0.002;
  the remainder is linear-vs-Sprague interpolation flavor, far below
  the metrics' integer-published precision.
- oracle tolerances tightened to just above measured (0.05/0.01/0.01)
  so any regression from today's agreement fails loudly.

161/161, nothing skipped.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: somejohnbforya

docs/whitepoint.js

@@ -16,6 +16,7 @@ import {
   CMF_1931_2, CMF_1964_10, sampleSpd, emissionToXyz, spectrumXy,
   planckianSPD, daylightSPD, cctOf,
 } from './index.js';
+import { CMF_1931_2_1NM } from './data-1nm.js';
 import { TCS_CIE1995 } from './data-tcs.js';
 import { CES_CIE2017 } from './data-ces.js';
 
@@ -70,8 +71,11 @@ const dKD = (u, v) => (1.708 * v + 0.404 - 1.481 * u) / v;
  */
 export function cri(spd) {
   const { cct, duv } = cctOf(spectrumXy(spd));
-  const ref = cct < 5000 ? planckianSPD(cct) : daylightSPD(Math.min(cct, 25000));
-  const cmf = CMF_1931_2;
+  const ref = cct < 5000 ? planckianSPD(cct, { step: 1 }) : daylightSPD(Math.min(cct, 25000));
+  // the 1 nm CMFs: F-series-style line+phosphor spectra are exactly what
+  // the abridged 5 nm tables mis-integrate (measured: 3–5× the residual
+  // against colour-science's 1 nm-practice computation)
+  const cmf = CMF_1931_2_1NM;
 
   const wt = uv1960(whiteXyz(spd, cmf));
   const wr = uv1960(whiteXyz(ref, cmf));

src/spectral/quality.js

@@ -28,9 +28,11 @@ test('CIECAM02 reproduces the CIE 159:2004 worked example', () => {
 });
 
 test('CRI of a reference illuminant is 100 by construction', () => {
-  const { Ra, Ri } = cri(planckianSPD(2856));
-  assert.ok(Math.abs(Ra - 100) < 1e-6, `Planckian Ra ${Ra}`);
-  assert.ok(Ri.every((r) => Math.abs(r - 100) < 1e-6));
+  // same 1 nm grid as the reference cri() builds internally — the
+  // construction holds only when test and reference share a representation
+  const { Ra, Ri } = cri(planckianSPD(2856, { step: 1 }));
+  assert.ok(Math.abs(Ra - 100) < 1e-4, `Planckian Ra ${Ra}`);
+  assert.ok(Ri.every((r) => Math.abs(r - 100) < 1e-4));
   // daylight: cctOf solves ~6502 for the 6504 synthesis — sub-0.5 wiggle
   assert.ok(cri(daylightSPD(6504)).Ra > 99.5, `D65 Ra ${cri(daylightSPD(6504)).Ra}`);
 });
@@ -84,9 +86,12 @@ test('agreement with python colour-science',
     const SPDS = { FL2: FL2_SPD, FL7: FL7_SPD, FL11: FL11_SPD, A: illuminantASPD(), D65: daylightSPD(6504) };
     for (const { name, Ra, Rf, Rg } of rows) {
       const ours = { Ra: cri(SPDS[name]).Ra, ...tm30(SPDS[name]) };
-      // tolerance covers 5 nm CES vs the oracle's 1 nm + interpolation policy
-      assert.ok(Math.abs(ours.Ra - Ra) < 1.0, `${name} Ra ${ours.Ra} vs oracle ${Ra}`);
-      assert.ok(Math.abs(ours.Rf - Rf) < 1.0, `${name} Rf ${ours.Rf} vs oracle ${Rf}`);
-      assert.ok(Math.abs(ours.Rg - Rg) < 1.5, `${name} Rg ${ours.Rg} vs oracle ${Rg}`);
+      // measured agreement: Rf/Rg ≤ 0.002, Ra ≤ 0.027 (the residual is
+      // linear-vs-Sprague interpolation flavor, far below the metrics'
+      // integer-published precision). Tolerances sit just above so any
+      // regression from today's agreement fails loudly.
+      assert.ok(Math.abs(ours.Ra - Ra) < 0.05, `${name} Ra ${ours.Ra} vs oracle ${Ra}`);
+      assert.ok(Math.abs(ours.Rf - Rf) < 0.01, `${name} Rf ${ours.Rf} vs oracle ${Rf}`);
+      assert.ok(Math.abs(ours.Rg - Rg) < 0.01, `${name} Rg ${ours.Rg} vs oracle ${Rg}`);
     }
   });