Effects of ESA on Dot Gain and Optical Density of Compressed and Elongated Cells
By Miles Haney
In this work it was determined how changes in the electrostatic assist (ESA) levels affect the optical density and dot gain of the gravure printed document. Optical density and dot gain of elongated and compressed cells at different ESA settings was also compared in this experiment. Two test targets at four different ESA settings were printed on a Cerutti four-color rotogravure press. Dot gain and optical density was measured for six tone steps of elongated magenta cells, compressed magenta cells, elongated cyan cells, and compressed cyan cells. For optical density values of compressed and elongated cyan and magenta for each ESA setting, elongated starts with a larger density value but as the tone step is increased, optical density values become larger for the compressed cells than that of elongated. Elongated cells are shown by this experiment to produce higher dot gain for both magenta and cyan than that of compressed. Elongated cells for both magenta and cyan to have a more stable trend of dot gain with less deviation than that of the compressed cells.