The audience pays in money, light and comfort for an effect it forgets

The argument

The second argument concerns what the format costs the person watching. Stereoscopic presentation requires filtering, because each eye must be given a different image, and the filtering removes light, so the picture is dimmer than the same film shown flat. Proponents argue that brightness is not a technical detail but a large part of how an image reads, affecting colour, contrast and the legibility of dark scenes, which are the scenes most often complained about. The glasses sit over the viewer's own if they wear them, have to be held in place, and for some viewers produce eyestrain, headache or nausea rather than immersion. Then there is the price. The format is sold at a premium, and proponents argue that the premium is the clearest test of whether it is necessary: if the effect were doing essential work the flat version would be the compromise, whereas audiences treat the flat version as the normal way to see a film and the stereoscopic one as an upgrade they are free to decline. The last step concerns memory. Proponents argue that the effect is conspicuous for a few minutes and then stops being noticed, because the visual system adapts and the viewer returns to following the story. What people recall afterwards is the performance, the images and the ending, not the depth. A feature which costs light, comfort and money, and which has left no trace by the time the audience reaches the street, is on this account the definition of something a film does not need.

Premises

Counter-arguments

Critics answer that every one of these costs is contingent on equipment rather than intrinsic to the format: brighter projection, better filters and lighter glasses reduce them, and the discomfort reported by a minority of viewers is a reason to keep a flat version available rather than to call the format unnecessary. They add that the argument from forgetting cuts against most of film technique, since audiences also stop noticing the sound design, the lighting and the cut, and none of those is thought dispensable for being invisible. Adaptation, on this view, is what a successful effect looks like: the viewer stops seeing the depth and begins inhabiting the space.

Rejecting the premises

[Rejecting P1] Light loss is a property of current projection and filtering rather than of stereoscopic presentation as such, and it falls as the equipment improves. [Rejecting P2] Discomfort is reported by a minority of viewers and argues for keeping a flat version on offer, not for judging the format unnecessary for everyone. [Rejecting P3] That an effect stops being noticed is the ordinary mark of a technique that works, as with sound design and editing, so adaptation is weak evidence of dispensability. [Rejecting C] At most it follows that the format is poorly implemented and badly priced, not that it is unnecessary.