Archived posting to the Leica Users Group, 1999/08/13

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Subject: RE: [Leica] Erwin's adventures in digiland. part 1 and 2
From: "Jean-Claude Berger" <jcberger@imaginet.fr>
Date: Fri, 13 Aug 1999 14:52:38 +0200

Hello Erwin,

Could this be a typo? I thought that each pixel was represented by 24
or 48 bits. How can 4 pixels represent 1 pixel?

> interpolation. Remember that 4 pixels are needed to record
> one image
> pixel.

On your second article, you say :

> As the typical inkjet printer has 6 colors only a limited range of
> colors and colorshades can be produced. All other colors and shades
> demand the use of a halftone or raster technique. If the printer
> would use a 2x2 matrix  5 additional shades can be produced. If we
> need the full range of shades a 16x16 matrix will b used.

Could you elaborate about the "5 additional shades can be produced"?

As far as I remember, on 6 colors printers, there are 4 (black
included) basic inks plus 3 see-through ones. So one dot may have 20
"colors/shades" (no ink, ink 1, 2, 3,..6, black, 1+4, 1+5, 1+6, 2+4,
...., 6+6). So a matrix of 4 dots will present 20 power 4
combinations. I do agree that some combinations are equivalent if we
consider only the global aspect of the matrix. For example, the square

A B
A B

will have the same color than the squares

B A
B A

or

A A
B B

but it will not give the same effect when the firmware uses
anti-aliasing algorithms that is the case, if my memory serves well,
with PCL 5 or PhotoEnhance.

Moreover, the 750 and 1200 Epson printers are said to be able to
control the amount of projected ink. That may lead to a greater number
of possibilities, no?


All the best.


 ---
 Jean-Claude Berger (jcberger@jcberger.com)
 Systems and RDBMS consultant (MCSE), Lyon, France
 http://www.jcberger.com