- Dots of ink and patterns:
All printers need several dots
to print one pixel, depending on printer technique. Note
that dpi is for dot per inch and shall be
different from ppi, pixel per inch. For example,
a 256 scaled grey pixel will require 8 dots or micro-drops
of ink with an ink jet printer. The soft of the printer
calculates and defines the number of dots, the size and
the location of each dot depending on the printing options
that can be set in the properties of the printer. Thus,
each pixel is printed with a pattern of ink drops.
The maximum number of ink dots
indicates the ability of the printer to produce quality
prints. It varies depending on the printer technique.
A pixel is equal to one pattern
of micro drops.
In a ink jet printer, the dot is
a micro-drop of ink.
related to digital printing:
In professional printing of magazines,
books, etc, the number of lines of patterns per unit of
length is used for defining printing conditions.
There are many patterns depending
on the printing techniques.
Unfortunately for amateurs, in
the window for setting the print size, most softs are indicating
dpi when requesting the number of pixels per inch
when it should be shown ppi.
Of course it is wrong and really
confusing. Now, that way is so commonly used, for scanners
and printers, and the number of ink dots being impossible
to set but necessarily calculated by the soft and unknown
by the user, it can be guessed that dpi shall be read as
ppi and is no more related to ink dots.