Presensitized

Presensitized describes a material or product that has been pre-coated with a photosensitive layer, making it ready for exposure to light to create an image or pattern. The term is used across several fields, including photography, printing, and printed circuit board (PCB) fabrication. In photographic and printing contexts, presensitized plates or films carry a ready-to-expose emulsion that, when illuminated by ultraviolet or other light sources, undergoes a chemical change. Depending on the process, the exposed or unexposed areas are then developed to reveal an image or to prepare a plate for printing.

In offset lithography and related printing technologies, presensitized plates (often abbreviated as PS plates) combine a backing material such as aluminum or a polymer with a light-sensitive coating. After exposure through a film or digital mask, the plate is developed to remove either the unexposed or the exposed areas, creating a printable image on the plate for subsequent inking and printing.

In PCB manufacturing, presensitized copper-clad boards are coated with a photosensitive resist. Exposure through a circuit pattern hardens the resist in the image areas, and development reveals the copper to be etched away, forming the desired traces.

Storage and handling considerations reflect the photosensitive nature of presensitized materials. They require protection from unintended light exposure, typically a dark or low-ambient-light environment, and have specified shelf lives. Proper storage, temperature control, and handling are important to maintain sensitivity and performance.

See also: photosensitive materials, photoinitiated processes, semiconductor and electronics manufacturing.