Trükkplaatide

Trükkplaatide is the Estonian term for printing plates, the sheets used to transfer ink to a substrate in various printing processes. The most common application is offset lithography, but printing plates are also used in other methods such as relief and gravure systems. A printing plate carries image areas that accept ink and non‑image areas that hold water or are ink-repellent, depending on the process.

Historically, printing plates were made from metals such as zinc, copper, or steel. In offset printing, aluminium plates became the standard due to their light weight, smoothness, and durability. Images were created photographically on the plate through photomechanical or film-based workflows, followed by chemical processing to reveal the image. With the rise of direct-to-plate technology, plates can be imaged directly from digital data using lasers, reducing or eliminating the need for intermediate film.

In operation, lithographic plates rely on the principle that the image area is ink-receptive and hydrophobic, while the non-image area is hydrophilic and attracts water. The plate is mounted on a press; impression and ink transfer occur via a blanket cylinder onto the substrate. Traditional plates often required chemical development, while computer-to-plate (CTP) plates image directly from digital files, typically with less chemical processing.

Modern practice increasingly uses direct-to-plate systems, including thermal and violet/green laser plates, which streamline workflows and reduce chemical usage. Trükkplaatide remain central to commercial printing, packaging, and publishing, though some digital printing technologies operate without traditional plates. Plate durability, run length, and substrate compatibility vary by type and application.