# Built-in colour books

AutoCAD `.acb` colour books built into the Select Color panel. Each file
carries its source and licence in its header comment.

| File | Book | Source and licence |
|---|---|---|
| `ral-classic.acb` | RAL CLASSIC, 216 approximate sRGB values | Adapted from Wikipedia, "List of RAL colours"; CC BY-SA 4.0 |

Values are approximate screen representations, not colour-binding
references. RAL is a registered trademark of RAL gGmbH; this file is not
affiliated with or endorsed by RAL gGmbH.