Extant pieces are ideal sources. For pre-Medieval devices, medieval depictions are very unreliable and should be supported by text references. Must have at least a 3X5 card. More is acceptable.
Materials used are period OR give period effect.
Style, pattern, design and finished product are consistent with one another and give period effect. Difficulty and variety of tools used. Difficulty and variety of construction techniques used. Difficulty and variety of decorative techniques used. Finishing techniques used.