DSS-Ch.03.02 — Mineral Staining (persistent film/discoloration, non-etch)

Mineral staining (non-etch) is a tenacious surface film or color shift caused by hard-water minerals/salts (often with organic/soiling binders) that persists after a proper Non-Invasive Reveal yet does not produce subsurface attack. Under magnification/raking, the glass substrate shows no modeled micro-texture when the stain is fully lifted-MSRT on clean substrate = SC-0. Classification here is appearance-only (method-agnostic). Inspect under VIS lighting/geometry and record surface numbering and worked-surface status on Forms:

• Residual tone/contrast shift (whitish, grey, brown, or iridescent cast) in the footprint of prior deposits/runs after normal cleaning.
• Halos or bands at drip edges, sills, or mullions; sheet-like veil that softens reflections at certain angles.
• Under raking: no granular/etched micro-texture on the substrate once an area is truly clean-appearance is optical film/contamination related.

Surface-catch class (MSRT)

• On the clean glass substrate: SC-0 (no relief).
• Across remaining film: avoid stylus use on contaminated patches; lift a small test spot (without abrasion) to expose substrate and confirm SC-0.
• Polymer stylus if a coating is suspected. MSRT supports classification only.

Visual signature

• Uniform or gently mottled veil; may track prior drip/run geometry, but edges are optically soft, not rimmed like etched boundaries.
• No chip-flank sparkle (separates from mechanical scoring). No discrete pits/nodules (separates from hot-particle).

Viewing / lighting

• Evaluate clean & dry at 12 / 36 / 72 in, normal incidence and oblique sweep (~60°-120°) with raking light on a revealed test patch to confirm absence of micro-texture. Document distances/angles in-frame.

Location / access

• Record pane ID and surface numbering (#1-#4; laminate-internal). If fixed parallax indicates a between-pane condition (cavity film), classify CAT-5 by location (out of in-place scope).

Mechanism cue (context)

• History of irrigation overspray, HVAC plume, coastal aerosol, or rinse sequences that left mineral/organic film; repeated wet/dry cycling without timely cleaning.

Assign CAT by visibility impact under VIS geometry after a controlled reveal test confirms substrate SC-0. Because staining is non-etch, depth values are not applicable (substrate relief remains 0-10 μm optical only).

• CAT-1 (Benign / non-relief): Faint veil/halo visible mainly in raking at close/standard; substrate SC-0 at the test patch.
• CAT-2 (Light): Noticeable film at standard view under certain angles; still SC-0 on substrate where film is fully lifted; edges soft.
• CAT-3 (Moderate): Persistent, broader veil/banding apparent at standard distance across larger area; SC-0 confirmed at localized lift.
• Reclassify when: Any modeled micro-texture or SC-class > 0 persists on the substrate after true film removal → Ch.03.03 Mineral etching (CAT-2/3/4 by cues).
• CAT-5 (by location/condition): Between-pane/inaccessible by parallax, integrity indicators, or confirmed functional-coating loss on the surface to be worked → CAT-5.

CAT is appearance-based; acceptance is separate under VIS-A at 12/36/72 in. Do not abrade to “force” removal during classification.

• vs. Mineral deposits (Ch.03.01): Deposits fully remove with no residual tone shift; staining persists optically but remains SC-0 on substrate when truly clean. vs. Mineral etching (Ch.03.03): Etch shows modeled micro-texture and SC-1/SC-2 after film removal; staining does not.
• vs. Alkaline/acid etch (Ch.01/.02): Chemical etch exhibits run-organized micro-texture and SC-class > 0; staining is a film/optical condition.
• vs. Coating anomalies (Co-family): Coating rub/patchiness may mimic a veil but will follow coating logic (on the worked coated surface any anomaly is not permitted at acceptance; VIS §6.2.e). Confirm coating presence.
• vs. Soot/detergent films (R-family): Many remove at reveal; persistent non-etch staining may require specialized film lifting (outside classification scope).

• Photo set (VIS): 12 / 36 / 72 in, normal + oblique; include pre-reveal overall, and a post-reveal test patch that demonstrates substrate SC-0 (raking macro). Record distance/angle in-frame.
• MSRT result (substrate only): One light, non-marring pass on the clean test patch; record SC-0 if non-etch is confirmed.
• Forms: Pane ID; product family & surface numbering; worked surface Y/N; functional coating present on worked surface? (Y/N/Unknown); reveal status; lighting/time; geometry checklist; photos attached.
• Acceptance split: Post-restoration acceptance per VIS-A §6; classification ≠ acceptance. Coated-face rules apply per VIS §6.2.e.

• Ch.03.02 Mineral Staining (non-etch) - Persistent surface film/veil on surface #___; post-reveal test patch confirms substrate SC-0 and no modeled micro-texture. Visible at [12/36/72 in] under VIS geometry. Morphology: soft halos/bands/veil; no chip-flank sparkle; no discrete pepper. Classification: CAT-[1/2/3] by visibility impact (non-etch). Reclassify to Ch.03.03 if SC-class > 0 persists on substrate. CAT-5 if between-pane. Forms + photo set attached; acceptance per VIS-A §6.