🚀 go-pugleaf

In article <g1xqbbty@csv.warwick.ac.uk> esurw@warwick.ac.uk (Stephen Landamore) writes:
>with having a narrow linewidth  and a grainy resolution of halftoning,
>I don't  really know. This  would  seem  to imply  that the above idea
>would be great in practice, you say it 'gives only a few distinct gray
>levels' ... just how many?

In simple halftoning (which is what most printers deal with) the number of
gray levels is approximately the square of the printer resolution divided by
the screen frequency, i.e. a 300 dpi printer at 60 lpi would have (300/60)^2
= 25 gray levels, plus one for all-white.  Some slight deviations in actual
gray levels result from the rotation of the screens, strange dot functions,
or special tuning within a screen to remove unpleasant dot structures.

Some printers have methods for increasing the gray levels of a given
frequency screen.  The most common of these is "supercell" techniques.
Check with a specific printer manufacturer for details of screening.  If you
assume too much, you may cheat yourself out of better image quality.

KD
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