Summer Steam Capsule Gradient Banding Fails Readability Squint After HDR Regrade - How to Fix

Problem: During July–August 2026 October Next Fest prep, art lifts sky/ground luminance for a “summer” HDR regrade. The 1232×706 main capsule looks smooth at 100% on a 4K monitor, February safe-zone Z still passes, but the 616×353 squint shows posterized gradient bands, detect_capsule_gradient_banding.sh exits 1 (banding_row_spikes too high), and BUILD_RECEIPT cannot honestly set summer_capsule_gradient_ok: true.

Who is affected now: Marketing + Blender compositor teams following summer capsule gradient art pass and Blender summer capsule gradient preflight (Guide #47). This is ramp banding recovery after HDR lift, not crop/safe-zone failure (February Z), not three-swatch ΔE alone (palette lock), and not false-bloom downscale (winter HDR tone art pass).

Fastest safe fix: Stop store upload → re-export with 0.5–0.8% noise on gradient layers only (Blender File Output sRGB 8-bit) → re-run B3 squint + B4 detect + B5 phone contrast → rewrite summer_capsule_gradient_receipt_v1.json → promote summer_capsule_gradient_ok: true.

Direct answer

Banding that appears only at half-res means the ramp was flattened too hard (8-bit / wrong dither / Display-P3→sRGB mishandle). Fix the export, not the store JPEG quality alone. Do not flip summer_capsule_gradient_ok while B3 is RED—shoppers see ~616×353, not your PSD zoom.

Why this issue spikes in July–August 2026

1. Summer sky lifts push wide HDR ramps into posterization on Steam grid downscale.
2. Judging at full resolution hides steps that appear after -resize 616x353!.
3. Noise applied to the whole capsule softens art without fixing the ramp (or kills title sharpness).
4. 16-bit PNG upload or Display P3 export without conversion creates unexpected banding in Steam’s pipeline.
5. Safe-zone GREEN theater — Z crop pass ≠ B banding pass.

Symptoms and search phrases

• “Steam capsule banding after HDR regrade”
• detect_capsule_gradient_banding.sh FAIL: banding row spikes
• B3 RED / “more than 3 steps” on sky behind title
• Capsule fine on desktop, striped on phone store grid
• summer_capsule_gradient_ok false while october_rc_label_ok true
• Discord screenshots of “posterized sky” on wishlist page

Root causes (check in order)

1. No ramp dither — ColorRamp / Gradient Texture flattened clean into 8-bit.
2. Full-capsule sharpen/noise — wrong layer; banding remains.
3. Squint never run — only 100% 4K review.
4. Script threshold uncalibrated — B4 fails on good art or passes bad art.
5. Title contrast fight — B5 darkening skipped after dither.
6. Crop confusion — treating February Z failure as banding (wrong receipt).

Beginner path (first 20 minutes)

Prerequisites: ImageMagick magick, write access to release-evidence/marketing/, current capsule_main_1232x706_*.png, Guide #47 or Photoshop/Krita equivalent.

1. Prove the failure at half-res:

magick release-evidence/marketing/capsule_main_1232x706_summer_v2.png \
  -resize 616x353! \
  release-evidence/marketing/capsule_616x353_squint.png

Open capsule_616x353_squint.png at 100%. Count sky/ground steps behind the title.

2. If >3 steps, reopen the master in Blender (or PSD): add 0.5–0.8% noise only on the gradient/sky layer, flatten to sRGB 8-bit PNG, re-export …_summer_v3.png via Compositor File Output (Guide #47 B2).

3. Re-run squint (B3). Target ≤3 steps.

4. Run banding detect (B4):

chmod +x release-evidence/marketing/scripts/detect_capsule_gradient_banding.sh
./release-evidence/marketing/scripts/detect_capsule_gradient_banding.sh \
  release-evidence/marketing/capsule_main_1232x706_summer_v3.png

5. Check 360px phone mock title contrast ≥4.5:1 (B5)—darken only behind the title bbox if needed.

6. Rewrite receipt + BUILD_RECEIPT (below). Do not upload on B3 RED.

Developer path (recovery gates)

R1 — Do not “fix” crop when ramps fail

If logos sit in the outer 8% or safe-zone overlays fail, stop and run February Z. This help assumes layout OK, ramps bad.

R2 — Blender recovery export

1. Compositor File Output: PNG, sRGB, 8-bit after dither.
2. Noise on sky/ground ramp only.
3. Path example: release-evidence/marketing/capsule_main_1232x706_summer_v3.png.
4. Cross-check palette lock—if ΔE > 8 from intentional summer lift, document palette_waiver (B1 YELLOW→GREEN with note).

R6 — Receipt rewrite

{
  "schema": "summer_capsule_gradient_receipt_v1",
  "iso_week": "2026-W29",
  "fest_name": "Steam Next Fest October 2026",
  "build_label": "fest-demo-2026-10-rc1",
  "recovery": {
    "reason": "B3_RED_after_hdr_sky_lift",
    "fix": "ramp_only_dither_0.6pct_reexport_v3"
  },
  "gates": {
    "B1": "GREEN",
    "B2": "GREEN",
    "B3": "GREEN",
    "B4": "GREEN",
    "B5": "GREEN",
    "B6": "GREEN"
  },
  "metrics": {
    "squint_step_count": 2,
    "banding_row_spikes": 9
  },
  "evidence": {
    "capsule_path": "release-evidence/marketing/capsule_main_1232x706_summer_v3.png",
    "squint_path": "release-evidence/marketing/capsule_616x353_squint.png",
    "banding_script_log": "release-evidence/marketing/banding_detect_log.txt"
  },
  "summer_capsule_gradient_ok": true
}

Promote:

{
  "summer_capsule_gradient_ok": true,
  "capsule_gradient_ok": true,
  "summer_capsule_gradient_receipt": "release-evidence/marketing/summer_capsule_gradient_receipt_v1.json"
}

jq -e '.summer_capsule_gradient_ok == true' release-evidence/BUILD_RECEIPT.json
jq -e '.summer_capsule_gradient_ok == true' release-evidence/marketing/summer_capsule_gradient_receipt_v1.json

Verification checklist

Prevention

1. Run Guide #47 before locking October capsule assets.
2. Add CI banding job on capsule_main_*.png paths (summer gradient blog).
3. Never declare store GREEN from full-res only.
4. Keep February Z and summer B receipts separate.
5. Schedule pass after every intentional HDR sky lift—not only first summer freeze night.

Common mistakes

1. Uploading while B3 is RED “to hit summer freeze.”
2. Sharpening the whole capsule after dither.
3. Flipping BUILD_RECEIPT without re-running detect.
4. Treating sale-sticker crush or JP/KR overflow as banding (Summer Sale sticker / multilingual typography cousins).
5. Confusing winter HDR false bloom (screenshot/capsule tone) with store capsule ramp banding.

Related GamineAI reads

• Summer Steam capsule gradient band readability pass
• Blender summer capsule gradient preflight (Guide #47)
• February fest capsule safe-zone Z
• Palette lock worksheet
• October RC label before summer freeze
• Steamworks store assets

Store grid lies when the PSD looks fine—recover with ramp-only dither, prove B3–B5 at half-res, rewrite summer_capsule_gradient_receipt_v1.json, then latch summer_capsule_gradient_ok.