P3D Re: Printer resolution (was Re: P3D Re: Lenticulars)

["Greg Wageman" <gjw@xxxxxxxxxx>]

From: Brian Reynolds <reynolds@xxxxxxxxx>


>The second thing to know is that printing is a binary operation.
>There is either ink at a particular location on the page or there
>isn't.  For the types of printers being discussed there are no shades
>of gray (or whatever the base ink color is).  Printers produce shades
>of gray by taking a small area and dividing it up into a grid.  The
>number of locations on this grid that get ink depends on the shade of
>gray that that area is supposed to have.  The number of shades of gray
>depends on how finely the area is divided into a grid.  A 2x2 grid can
>produce 4 shades of grey, a 4x4 grid can produce 16 shades of gray,
>and a NxN grid can produce N^2 (N squared).  To get 256 shades of grey
>you need a 16x16 grid.  The small area is a pixel, and a location on
>the grid is a dot.


I wrote about this subject on Friday, and you didn't even copy the
numbers properly... :-)

A 2x2 grid produces *five* levels, not four.  Count them: 0 dots
(white), 1 dot, 2 dots, 3 dots, 4 dots (black).  A 4x4 grid produces
*17* levels, not 16.  The function is n^2 + 1, not n^2.

     -Greg W. (gjw@xxxxxxxxxx)



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