The substrate library
Corrugated polypropylene — coroplast — is light, weatherproof and cheap, the standard for temporary outdoor signage and short-run POS. Aluminum composite material such as Dibond is two aluminum skins bonded to a polyethylene core; rigid, genuinely weatherproof, V-groove foldable and the go-to for permanent exterior signage. Expanded PVC, sold as Sintra or Komatex, gives a smooth matte face and machines beautifully for interior dimensional lettering. Foamboard and Gatorfoam suit lightweight interior display. Acrylic and polycarbonate handle backlit faces, standoff-mounted panels and anything needing clarity or impact resistance.