Halftoneteknikken

Halftoneteknikken, or the halftone technique, is a printing method used to reproduce images with continuous tonal variation by means of a grid of small dots. Instead of varying ink density across a smooth tone, the image is represented by the size or density of discrete dots arranged in a halftone pattern. When viewed from a normal distance, the dots visually blend to form shades of gray or color.

The basic principle involves converting a grayscale or color image into a set of interlaced dots. Each dot’s size or density encodes the luminance of its area. In color printing, separate halftone screens are created for each color channel (typically cyan, magenta, yellow, and black) and then printed in succession to produce a full-color image. The spacing, angle, and frequency of the screens affect sharpness and can lead to moiré patterns if not managed properly.

Historically, halftoning emerged in the late 19th century with the development of photomechanical screening techniques. Early practical implementations were advanced by innovators such as Frederic Ives, and halftone printing rapidly became standard in newspapers, magazines, and other mass-produced prints by the end of the 1800s. With the advent of digital imaging, halftoning evolved into a suite of algorithms and screening methods.

In modern practice, halftoning encompasses several approaches. Amplitude-modulated (AM) halftoning varies dot size on a fixed grid; frequency-modulated (FM) or stochastic screening uses a fixed dot size with controlled distribution to reduce visible patterns. Common digital methods include error diffusion, ordered dithering, and stochastic screening, all designed to reproduce tonal detail while leveraging standard ink or toner-based printing processes.