> -----Original Message-----
> From: owner-filmscanners@halftone.co.uk
> [mailto:owner-filmscanners@halftone.co.uk]On Behalf Of Arthur Entlich
> Sent: Wednesday, February 28, 2001 2:09 PM
> To: filmscanners@halftone.co.uk
> Subject: Re: filmscanners: File sizes, file formats, etc. for printing
> 8.5 x 11and 13 x 17...
> Some top end high res laser printers (I believe HP owns the patents) can
> actually vary dot size within a set matrix to produce a half-tone
> screen, although the control of dot shape and size on a laser printer is
> still not to the quality of a imagewriter.
>
> Art
I don't believe imagewriters need to use dot-size modulation, do they? They
are at a true 2400 dpi and can use a 16X16 dither cell for 256 gray levels
with no trickery while still achieving 150 lpi, which is mighty fine
printing of half-tones.
Also, it isn't just top end lasers that use dot size modulation. HP's RET
(which stood for something like Resolution Enhancement Technology) was used
for years on all models of LaserJet III's through I don't know what model
(lost track). With true 1200 dpi now readily available, it really isn't
necessary anymore, but I believe some manufacturer's still use similar
technology, like NEC to achieve 1200dpi appearance with 600 dpi true. I used
to be in the laser printer biz and remember this stuff well. HP's original
claim was to achieve the effect of 600 dpi using 300 dpi, through the use of
four different dot sizes (including null, so really 3).
Frank Paris
marshalt@spiritone.com
