The method is for setting the line width of recorded image lines of a
focused image beam in an exposer. The exposure point has a diameter and an
area with a non-uniformly distributed power density. The recording
material has a first exposure threshold and is exposed with an energy
density near a second exposure threshold that is substantially higher than
the first exposure threshold. The recording material can be a photopolymer
printing plate. The line width of the recorded image lines is determined
from the distribution of the power density over the area of the exposure
point by integrating the time variation of the power density resulting
from the exposure speed of the laser beam. The line width is set, by
changing the diameter of the exposure point and/or by the laser power,
such that the line width is substantially equal to the line spacing.
