General shifts

spikes/card-harness/README.md

@@ -27,6 +27,32 @@ Transform gizmos and a general timeline are intentionally deferred. The separate
 
 ## Tear-open foil pack prototype
 
+### Experimental materials and finishes
+
+The toolbar, Lab controls, saved experiments, and random pack pool share the same
+available choices. The following treatments are visual trials, not approved defaults:
+
+- **Leather material:** shallow, softly rounded grain, restrained warm ink absorption,
+  and a brown edge. Mask-protected ink stays smooth; artwork and lettering stay anchored.
+  The original dense, deeply recessed grain was rejected for poor readability.
+  The current trial uses moderate soft-grain relief (0.0032 scene units at default
+  detail), between the original harsh treatment and the overly faint first revision.
+- **Gold leaf finish:** warm metallic gilding with fine irregular folds and mottling,
+  rather than ordinary foil's mostly color-preserving sheen.
+  Its gold range and highlights are compressed, with more original ink retained,
+  to reduce contrast without removing the folded texture.
+- **Frosted glass finish:** cool satin haze and fine etched microrelief, without
+  transparency or blurring the underlying artwork.
+
+Vellum and Pearlescent were removed after visual review because they were not
+sufficiently distinct. Older experiments using either report an unsupported format.
+
+All finishes follow the supplied finish mask, including text protection. Leather also
+uses the mask to suppress grain over protected ink. Other material textures cover the
+substrate independently of that mask. Finish strength controls
+the new coatings; Surface detail controls the material relief. No card-specific
+regions, artwork generation, or additional texture files are required.
+
 Choose **Pack** in the Mode selector (expand **Controls** first on mobile).
 Use **Pack style** in the same toolbar to compare three wrapper-only design studies: