A brief overview
Four primary variables are manipulated in the screening technologies that are used to produce the dot patterns formed on offset and flexo printing plates. These are dot size, dot frequency (number of dots in a given area), dot formation, and most recently, dot shape.
Conventional AM (amplitude modulated) screening changes the dot size through the entire tonal range, while maintaining a fixed center spacing on the dots, denoting the lineature. A smaller overall dot size can provide a higher line per inch (lpi) screen, while lower lpi screens use larger dot sizes. The choice of which to use is determined by several printing and substrate factors. AM screening generally provides good reproduction in the mid-tones, but runs into problems in the highlights (below 10 percent) and shadows (above 90 percent), especially in flexo.
- Companies:
- Agfa Corp.
- Artwork Systems
- Creo
- Phototype
- People:
- Frances Cicogna