Each print in this series (originally twelve in number; one has been lost) is composed of up to three superimposed images and is unfixed—that is, the chemical development of the image on the paper has not been halted as it is in an ordinary photograph. Thus, when they are exhibited, the photographs gradually darken to illegibility. Heinecken layered works by his photographer friends Jerry Uelsmann and Les Krims, among others. Heinecken stipulated that these pictures should be displayed four at a time and swapped out at regular intervals.