Official Unicode SignWriting and Facial Writing

This technical note states a production boundary for Sutton SignWriting facial writing: the official Unicode SignWriting head-plus-mark facial model should not be used as the basis for production text. The note evaluates the official Unicode model by the preservation function production users are likely to assign to it. It argues that Sutton SignWriting production text must preserve the written sign the author composed, including selected facial symbols, authored facial arrangement, sign boundaries, and authored spatial relations. For facial writing, official Unicode stores U+1D9FF SIGNWRITING HEAD plus nonspacing facial marks. That head-mediated sequence does not preserve the Sutton SignWriting facial symbols the writer selected or the authored facial arrangement, and later rendering, added coordinates, higher-level protocols, conformance tests, or implementation claims cannot recover production data the sequence never stored. This document DOI record includes the compatibility matrix and Unicode SignWriting production warning as companion packet files for readers who need a compact comparison or implementation-facing warning.