Digital BW, The Print

----- Original Message -----
From: "Austin Franklin" <darkroom@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Monday, August 05, 2002 7:08 PM
Subject: RE: [Digital BW] Number of tones was Re: Do inkjets dither or not?


> My interest is if Piezo can even print near that many tones as he has
> claimed (1000), as well as can we even see them....as well as, if it does,
> how does it derive them.  His comment had nothing to do with that,
> unfortunately.

The physical aspects of bringing ink on paper; bleed etc, that makes it
difficult to get the desired 256 tones on paper are at least spread over 4
grey inks. Unlike with full colour there's no need to get a max of 3 dots of
each at the same spot/area so less bleed. I doubt you can just multiply the
256 x 4, but there is of course an advantage. The use of the different greys
isn't divided that strict over percentage ranges and they will weave into
one another at the boundaries. Even if they overlap till half the next grey
then the total ink amount is much lower than in CMYK printing. Say all the
inks starts at 1 % and end at 80 % (unlikely it will be more complex), then
there still is a spread possible of approx 200 x 4. We don't see them, most
paper/ink combinations will not even make them but in theory with the best
paper/ink combination possible they can be printed. Whether the extra greys
steps input were available with a 16 bit image or by interpolation in the
driver stage doesn't matter. Of course the last builds on less information
than the first but that can be done quite clever.

Ernst