PCB material stack and display palette
The three fixed fabrication containers and their display colors, from palette.ts.
Three fixed material containers
Every document has exactly three fabrication roots in physical bottom-to-top order:
| Container | Role | Effective display color | PCB meaning |
|---|---|---|---|
| Copper | copper | gold (#d4af37) | Exposed copper with the product's HASL finish |
| Solder mask | solder-mask | black (#151515) | Solder-mask openings—artwork removes mask |
| Silkscreen | silkscreen | white (#f2f0e9) | Printed silkscreen |
The Layers UI reverses that order so the visible top surface appears first: Silkscreen → Solder mask → Copper. These roots are structural PcbLayerContainers, not ordinary groups. Their roles, ids, labels, order, and material colors are fixed.
Membership is authoritative
A vector object's owning container determines every non-null fill and stroke at projection time. Moving an object between containers therefore changes its material. Legacy color, fill, and stroke indexes remain in the JSON for backward compatibility and to represent whether path fill or stroke is enabled, but they do not override container membership in v5.
Solder-mask artwork is inverted (palette.ts, mask-sheet.ts): a drawn region is an opening where the mask is removed, exposing the gold/HASL copper below—or the bare FR4 substrate wherever no copper lies under that opening. A visible but empty Solder mask container is therefore full mask coverage, and a hidden one means no mask at all. A hole in an even-odd path punches back into the opening, so that area keeps its mask. Raster image layers are design references only. They live in Copper by default but are excluded from manufacturing and 3D material maps.
Compatibility color indexes
type ColorIndex = 0 | 1 | 2;| Index | Name | Owning role |
|---|---|---|
0 | black | solder-mask |
1 | gold | copper |
2 | white | silkscreen |
The hex values are display approximations, not fabrication swatches. The exported palette field remains a derived, advisory mapping for older readers; the v5 layers stack is the authoritative fabrication model.