Optical Dot Gain Study on Different Halftone Dot Shapes

Optical dot gain occurs because of the fact that a photon entering the non-inked substrate might scatter underneath a dot and be absorbed instead of reflected. This effect is dependent on the optical properties of the materials (paper, ink) and geometrical distribution of ink dots such as printing resolution, dot size and shape. In this paper, we compare the optical dot gain of halftone dots with different shapes and perimeters but with the same area size. For these purposes six dot shapes halftoned by using three different halftoning methods are considered for investigation. An effort is made to keep the area of the dot shapes constant for all six samples. Comparing the optical dot gain for different dot shapes shows the dependency of optical dot gain on the dot shape perimeter. Here we also show that there is a limit at which the optical dot gain is saturated. The dependency of optical dot gain on the dot shape perimeter verifies the fact that the amount of optical dot gain is different for different types of halftoning.