[2] Any dust spots or scratches appear as dark marks in the infrared, making them easy to find and compensate for.
Infrared cleaning does work with chromogenic black-and-white films, which do not contain silver particles.
Some film dyes also block infrared to a considerable extent; infrared cleaning works with Ektachrome slide film, but it is more difficult to find dust spots with the infrared-blocking dyes used in Kodachrome.
Some software algorithms, such as the latest ICE implementation (Nikon Super Coolscan LS-9000 ED with Digital ICE Professional[3]), VueScan's[4] and SilverFast's,[5] claim to use infrared cleaning to find dust spots even when scanning Kodachrome.
Canon could not use the trademarked Digital ICE name, so instead called it Film Automatic Retouching and Enhancement (FARE).