DSS-Ch.01.01 — Acid-Etch Graffiti (HF / BOE)

Acid-etch graffiti is a chemically etched pattern (letters, tags, symbols, swirls) produced by hydrofluoric-bearing agents (e.g., HF gels, Buffered Oxide Etch/BOE). Reaction dissolves silica, leaving subsurface micro-texture (“frost”) and often drip legs or pooling halos. Classification is appearance-only per VIS (method-agnostic). Inspect after Non-Invasive Reveal under VIS lighting/geometry; record surface numbering and worked-surface status on Forms:

Safety note (informative): treat any fresh, wet, or unknown residue as hazardous; do not touch-document visually and defer cleaning to site protocols.

• Readable tag geometry (initials, loops, strokes) with soft-edged “frosted” fill; contrast increases on dark backdrops.
• Drip legs descending from stroke ends; puddle/stop halos at start/finish points; occasional brush/dauber width consistency.
• In raking light, etched areas exhibit non-directional, modeled micro-texture (whitish haze) rather than linear scratches.

Surface-catch class (MSRT)

• Typically SC-2 (clear) within etched strokes; can read SC-1 at lighter attacks. Perform one light, non-marring pass; do not abrade. Use polymer stylus if a coating is suspected. MSRT supports classification only.

Visual signature

• Continuous, filled strokes (not just line scratches), with soft boundaries and no chip-flank sparkle; drip legs and pooling halos common.
• No discrete pits/nodules (separates from hot-particle pepper). No abrasive flank sparkle continuous over long run-length (separates from mechanical scoring).

Viewing / lighting

• Evaluate clean & dry at 12 / 36 / 72 in using normal incidence and oblique sweep (~60°-120°) with raking light to resolve modeled 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 presentation, classify CAT-5 by location (out of in-place scope) and refer per protocol.

Mechanism cue (context)

• Presence of acid applicators (daubers/etch-cream tubes), glove prints, or fresh chemical odor; proximity to public-facing elevations and transit nodes.

Assign CAT by appearance + MSRT + morphology (three-part cueing). Depth bands are indicative; numeric measurement not required.

• CAT-2 (Light): Thin, pale strokes with SC-1 to light SC-2; visible mainly under raking; minimal contrast at standard view. Indicative relief: ~10-40 μm.
• CAT-3 (Moderate): Readable tag with SC-2 across strokes; modeled micro-texture clearly apparent at standard distance; drip legs/halos present. Indicative relief: ~40-120 μm.
• CAT-4 (Severe): Dense, frosted fill or repeated over-etching with strong SC-2, high contrast at standard & wide-field views; occasional milkiness beyond stroke edges. Indicative relief: ~120-300 μm+.
• CAT-5 (by location/condition): Between-pane/inaccessible by parallax, active cracks/pane instability, or confirmed functional-coating loss on the surface to be worked → CAT-5 (non-repairable/out of in-place scope).

CAT is appearance-based; acceptance is separate under VIS-A §6 at 12/36/72 in. Do not “probe” with MSRT.

• vs. Mechanical scratch graffiti (M.01 / V.01.02): Mechanical tags show directional lineation with abrasive chip-flank sparkle along edges; acid-etch reads as filled, frosted strokes with modeled texture.
• vs. Etch-cream (consumer) patterns (V.02.02): Creams can mimic HF but often yield more uniform matte with cleaner stencil edges; industrial HF/BOE shows runs/drips and variable intensity.
• vs. Paint/marker coatings (V.03.01 / R.02.01): Coatings sit on the surface and remove at reveal; acid-etched areas remain with SC-class > 0.
• vs. Alkaline cement/mortar etch (Ch.02.01/.02): Alkaline attacks appear as flow fields and sheeting patterns tied to runoff; HF tags show intentional stroke geometry and drip legs from application points.
• vs. Coating anomalies (Co-family): Coating rub/patchiness yields sheen/color shifts but no etched relief; on a worked coated surface any anomaly is not permitted at acceptance (VIS §6.2.e).

• Photo set (VIS): 12 / 36 / 72 in; normal + oblique; include raking macros that resolve modeled micro-texture within strokes, plus at least one context frame capturing full tag geometry and surroundings. Record distance/angle in-frame.
• MSRT result: One light, non-marring pass on a representative stroke to record SC-class (SC-1/SC-2). Polymer stylus if coating is suspected.
• 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 at 12/36/72 in; classification ≠ acceptance. Coated-face appearance rules apply per VIS §6.2.e.

• Ch.01.01 Acid-Etch Graffiti (HF/BOE) - Etched tag strokes with [SC-1/SC-2] on surface #___, visible at [12/36/72 in] under VIS geometry after Non-Invasive Reveal. Morphology: frosted fill, modeled micro-texture, [drip legs/pool halos present/absent]; no chip-flank sparkle. Classification: CAT-[2/3/4] by relief/visibility; CAT-5 if between-pane, integrity cues, or coating-side loss on the surface to be worked. Forms + photo set completed; acceptance per VIS-A §6 (separate).