contactprinting

Contact printing is a printing or reproduction technique in which an image is transferred by placing a source image in direct contact with a photosensitive or inking medium and either exposing it to light or applying pressure. The resulting image is typically the same size as the source, making it useful for proofing, direct positives, or copying artworks and layouts. The term is used in photography, printing, and, in microfabrication, microcontact printing.

In photography, a negative or other image is laid against photographic paper or another sensitized support inside a light-tight frame. When the arrangement is exposed to light, the image is transferred without enlargement, producing a print with the same dimensions as the original negative. Depending on the paper, the print may require chemical development (developing-out or silver halide processes) or may appear after exposure without development (printing-out papers).

Materials include silver gelatin papers, cyanotype papers, or other light-sensitive media, placed under a glass to maintain flatness. The resulting outputs include contact prints and contact sheets, the latter displaying many frames from a roll for selection before enlargement. Advantages include sharpness and exact size; limitations include fixed scale, need for a sharp original, and grain or diffraction at size limits.

In microfabrication and art, contact printing appears as microcontact printing and related relief-transfer methods, where a stamp-like interface is pressed onto a substrate coated with a material such as polymer or ink to transfer a pattern with high fidelity. Modern practice often uses digital workflows to create negatives or masks for contact printing or to produce contact sheets for archival or documentation purposes.