Syväpainolevy

Syväpainolevy, often translated as photogravure or heliogravure, is a photo-mechanical printing process used to reproduce images. It is known for its ability to produce prints with a wide tonal range and fine detail, making it suitable for fine art reproductions and book illustrations. The process begins with a copper plate that is coated with a light-sensitive material, typically a gelatin or carbon tissue. This coating is then exposed to a positive photographic image.

Following exposure, the plate undergoes a development process. Areas of the coating that received more light become harder, while less exposed areas remain softer. The plate is then etched, usually with an acid solution. The etching process creates a recessed surface on the plate where ink will be held. The depth of the etching corresponds to the tonal values of the original image; darker areas of the image result in deeper etchings on the plate, allowing them to hold more ink.

Once etched, the plate is inked. The ink is applied to the surface and then wiped away, leaving ink only within the recessed areas. The plate is then placed on a printing press, and dampened paper is pressed against it. The pressure transfers the ink from the recessed areas of the plate to the paper, creating the printed image. Syväpainolevy prints are characterized by their rich, continuous tones and subtle gradations, often resembling traditional photographic prints. The process is relatively slow and labor-intensive compared to other printing methods, but its high quality justifies its use for demanding applications.