Acetate (Eyeglass Frames)

Cotton fiber and wood pulp go in, and a dense plastic sheet comes out. That sheet is dyed or laminated in layers, sliced into blanks, cut to shape, then tumbled with wooden pegs and polish for days until the surface shines without lacquer. Color runs through the whole thickness of the material rather than sitting on top. So a scratch on an acetate front shows the same color underneath and can be polished away.

Heat is the property that matters day to day. Acetate softens near 175 F, which is why an optician can drop a temple into a hot air blower, bend it, and have it hold the new angle once cool. The same softening point is why a dashboard in summer ruins a frame. Most acetate temples hide a metal core wire running most of their length. This is what lets a bend stay put instead of springing back. You can feel its end by flexing the temple and finding where stiffness stops. Injection molded plastic mimics the look at lower cost and gives itself away with a parting seam along the inside of the temple, a hollow sound when tapped, and much poorer response to heat.

Metal frames beat acetate on weight and on nose fitting, since they carry pads on bendable arms. Titanium halves the weight outright. What acetate answers back with is bulk and color. Nothing else can be cut 6mm thick, patterned like tortoise, or laminated so the edge shows stripes. Acetate is nearly always built as a full rim, so it also inherits everything that construction does well.

Wide faces, strong prescriptions needing thickness hidden, and anyone who reacts to metal against skin do well here. Cold climates favor it too, as plastic does not chill against your face the way an alloy does.

Press a fingernail along the inside of a temple hunting for that molding seam. Real acetate feels dense and slightly warm. It should have a plate or rivets anchoring the hinge into the plastic rather than a hinge pushed into a bare slot. Ask whether the bridge can be adjusted, since some can be warmed and squeezed slightly and some cannot. Store it away from radiators and never park it on your head, because splaying the temples on acetate is the one bend that will not come back on its own.