DSS-Co.01.02 — Color Non-Uniformity / Patchiness (sputtered low-E & multilayer films)

A localized change in color cast, tone, or optical density within a sputtered low-E or other multilayer functional coating on an exposed face (#1 or #4, as applicable). Presents as patchy zones, clouds, or bands without chip-flank fracture morphology. Under VIS, such coating anomalies are “coating anomalies (visual)” and are treated as appearance cues on the worked surface-not between-pane/system features.

• Pane-local patches or clouds of slightly different hue/brightness; strongest under raking light and oblique sweep; may align with prior contact paths (pads/cloths).
• No discrete chip flanks or cratered texture (unlike mechanical/thermal damage).
• Persists after Non-Invasive Reveal (clean & dry); if removal occurs, the cue was a face film/residue, not a coating anomaly.

Surface-catch class (MSRT):

• Expect SC-0 (none) if the cue is a pure coating-appearance change. Perform one light, non-marring pass only; prefer a polymer stylus on suspected coated faces-or rely on visual/location cues to avoid disturbing the coating. MSRT supports classification only, not acceptance.

Reveal / lighting / geometry:

• Complete Non-Invasive Reveal (clean & dry; no blades/chemicals) before evaluation. Inspect at 12 / 36 / 72 in, normal incidence + oblique sweep (~60°-120°) with raking light, per VIS.

Location / access:

• Confirm the observation is on the exposed coated face (not in an IGU cavity or laminate). Record pane ID and surface numbering on forms; note “functional coating present on worked surface? (Y/N/Unknown)”.

• Typical CAT band (appearance-based):
• CAT-1 - non-tactile color patchiness; SC-0; no edge morphology at acceptance geometry.
• CAT-2 - subtle micro-texture within the patch yielding SC-1 (slight).
• CAT-3 - pronounced, patchy modeled micro-texture detectable at standard distance, still without chip flanks. (Assign CAT by observable cues using VIS visibility convention + MSRT outcome.)
• Acceptance split (critical): Even if classified CAT-1...CAT-3, coating anomalies on the worked surface are not permitted at acceptance under VIS coatings guidance (see project-spec phrasing referencing VIS §6.2.e).

• For true coating patchiness, glass-face relief is typically nil at MSRT (SC-0). Numeric μm depth is not determinative for coating-appearance anomalies; VIS acceptance is appearance-only at the required distances/angles.

• vs. Mechanical scratches (M.01): Scratches show chip flanks/micro-chipping and SC-2 along a line; coating color patchiness lacks flanks and is area-based.
• vs. Face films/residues (R-family): Residues change with Non-Invasive Reveal; a true coating patch persists after reveal.
• vs. IGU/internal haze (A.01.01) or cavity fines (A.01.03): Internal cues exhibit fixed parallax and are CAT-5 by location; coating anomalies are on the worked face.

• Photo set (VIS): 12 / 36 / 72 in, normal + oblique, include raking; add a macro frame showing boundaryless patchiness (no chip flanks/transition edge). Note reveal status and lighting/time.
• MSRT result: Record SC class (expect SC-0); one pass, non-marring; on coated faces prefer polymer stylus or visual-only.
• Forms: Pane ID; surface numbering; worked surface Y/N; functional coating present on worked surface? (Y/N/Unknown); geometry checklist; photos attached.

Trying to “blend out” a color patch can enlarge the anomaly and create a worked region/transition edge, which VIS disallows at acceptance for CAT-0...CAT-4. Confirm reveal, SC class, and location before any action.

• Co.01.02 Color Non-Uniformity / Patchiness (sputtered stack) - Localized color/brightness variation at #__ verified after Non-Invasive Reveal; MSRT = SC-0; no chip flanks. Classified CAT-1...CAT-3 by visibility/texture per VIS. Acceptance note: Coating anomalies on the worked surface are not permitted (see project spec language referencing VIS §6.2.e). Document at 12/36/72 in (normal + oblique + raking), record surface numbering and coating presence, and attach photo set.