I've been looking at the Art Deco typefaces in an attempt to identify what traits constitutes it being 'art deco'. Therefore the following qualities, but not limited to, are significant to art deco typefaces (this is only a brief list so far as I am continuing to assess the typefaces):
Condensed
Sans serif
Crossbars/cross strokes at extremes i.e. susbstantially above or below the x-height
Stresses on certain letters (mostly e or o)
Extension of cross bar on certain letters in upper case such as A, E, F, H (varies from typeface)/could be viewed as a serif
Varying line width i.e. one stem thick whilst another line thin.
Exaggeration of specific letters i.e. a smaller o with an underline
