Fade To Black
One of the crazier films produced by Polaroid in an attempt to use up old expired chemicals was called SX-70 TZ-Artistic Fade To Black. This film was made with materials that normally would have been just chucked in the bin as faulty because the prints produced using Fade To Black film just fade completely to black over a period of 12 to 24 hours. Some people (far artier types than me!) enjoyed the ephemeral nature of these prints as an artistic statement in itself. But the colours of the print went through a serious of interesting changes during the fading process and when the print reached a state you liked you could slice open the print to let the chemicals dry and arrest the process. You could then tape up the print again to produce a permenant image.
