KPR

KPR, originally known as Kodak Photoresist, is a photosensitive material used in photoengraving, Photogravure and photolithography.

However, after exposure to strong ultraviolet light, it hardens and becomes insoluble by some of these solvents.

While they were developed primarily for photolithography for high-speed print setting for uses such as newspaper printing, their perhaps highest value came from their ability to produce non-conducting layers on top of conducting layers to precise dimensions.

This enabled the "printing" of large scale, closely placed conductive and non-conductive pathways to create binary gates.

It is ironic that Kodak, the original patent assignee, did not really participate in the economic juggernaut that it created through this lithographic printing technology.