Polaroid Corp has developed a 3.5 floppy disk capable of storing 20Mb as part of a major project to come up with a cheaper set of technologies for instant photography. It needs the high capacity disk to get adequate picture resolution and colour range, and its idea is to combine it with two other new technologies to create the instant camera of the 1990s. Images would be captured on the disk, and passed to another new device, a semiconductor diode laser that generates heat, the intensity of which would be governed by data from the disk. The lasers would be used to activate molecular switches on a new thermal picture film. These devices are switched on by heat, and change shade and intensity according to the degree of heat applied. Polaroid, Cambridge, Massachusetts, is also doing a drive for the disks.