Not just typical of 1940s Hollywood’s fondness for psychological subject matter The Dark Mirror is a showcase of aberrant behaviour and society’s sure-fire way of corralling and eliminating it.
Adapted by Nunnally Johnson (who also produced) from an original story by Vladimir Pozner, the core idea is refreshingly original although director Robert Siodmak’s realization is at best dutiful, at worst musty despite the production having top drawer creatives like Dimitri Tiomkin providing the niftily programmatic music and Milton Krasner as director of photography not to mention Johnson himself as writer.
Olivia de Havilland plays twin sisters, Ruth and Terry Collins, one of whom it is established early in the piece has murdered a man. The problem for the investigating Police Lt. Stevenson (Thomas Mitchell) is that whilst one of them has a water-tight alibi, leaving the other as the killer, neither will ‘fess up which is which so he cannot make an arrest. But hey-ho who should happen to be one of the people involved but Dr. Scott Elliott (Lew Ayres), a psychologist with expertise in identical twins. The girls agree to be examined by him and inevitably after a raft of Rorschach blots, word association tests and lie detector readings and finally a clever ruse by homely old Stevenson, the truth comes out.
All of this may have been a good deal more captivating to cinema-goers in the mid ‘40s but today the earnest psychologising comes across as completely tin-pot (which may have appeal for some modern viewers). If there is a measure of ambiguity at the outset by the mid-way point it has been well-established which is the good twin and which the bad, an opposition that grows more black and white as the film diligently works its way to the risible resolution with, disappointingly, no twist along the way.
For all that, Krasner handles the identical twin aspect impressively and there is some fun to be had from keeping track of which one is which (Tomkins’ music is very playful in this respect), Siodmak keeps the story moving along and De Havilland’s acting has plenty of nicely over-wrought moments, if that’s your thing.