Digital BW, The Print

Hi Roy,

> I can't imagine what code you've written.  Have you ever used a
> high level language?

Er, yes.  I've written a Lisp interpreter as well as a couple of C
compilers.  I've designed and coded at least six OSs as well as done a lot
of Unix kernel and driver work, along with many applications programs...from
a heuristic backgammon playing program to entire embedded control systems.
I've architected some rather large and very complex software (and hardware)
systems.  It's part of what I do for a living, and have been doing for over
25 years.

> What C construct are you going to use to
> test the carry bit out of the last arithmetic add?  Write me the code.
> If you prefer a different high level lang, use that.

That's up to the C compiler what it does.  Different C compilers will do
different things with the same constructs.  You should know that.

> Well the Epson drivers take RGB input.  You have to give it what it wants.

Apparently so.

> > > The idea is "partitioned" use of the inks.  There is actually
> > > lots of overlap, but conceptually think of it like this:  The
> > > darkest 25%
> > > (100% to 75%) of the tones are all done by the 100% black ink.
> > > The next 25%  (75% to 50%) is done by the 75% black ink, the next 25%
> > > (50% to 25%) is done by the 50% black ink, and finally the
> lightest 25%
> > > (25% to 0%) is done by the lightest 25% black ink.
> >
> > I understand that is one way of doing it, I hadn't said otherwise.
>
> Do you understand how it works and why it is so much better?

Why what works?  Why use four inks?  Of course, I've stated how it works,
and what the advantage is many times.

> > > The overlap and
> > > smooth joining of the partitions is tricky -- this is where Paul Roark
> > > has spent many, many hours designing curves to create this
> partitioning.
> >
> > I would believe that.  I've never done any design work using
> quadtone inks,
> > so this (thinking about dithering with quadtone inks) is all new to me.
>
> If its new to you, how can you make such assured claims as:
>       I still don't believe it prints "more than 1000" tones.

I can say what I don't believe very easily...it only means I personally
don't believe it...it doesn't mean it isn't "possible".  Cripes Roy.  Also,
because I have a LOT of experience with dithering algorithms, as well as a
LOT of experience with Piezo, as well as a LOT of experience with darkroom
printing...and with printing in general as well as a LOT of experience with
digital imaging...

> The quad inks give an exponentially better system.

I guess that depends on what your exponent is...  No one disputes it's
better.

> Plus it can be done in a much smaller area.

Do you not read what I write?  I've said that in just about every post...

> Droplet sizes multiply again.

Droplet size is applicable to single ink dithering as well as multiple ink
dither.

> Easily dozens or maybe a 100 times better.  Then didn't I calculate
> 576 pixels under the densitometer?  That's another 500 multiplier.

How's that work?

> How about the stochastic screening.

What about it?  I've done quite a few stochastic screening algorithms.

> > > I was thinking of creating some of those step wedge and gradient files
> > > that have been talked about -- and some others that may be useful.
> > > I'm not running piezo lately and don't have access to a densitometer
> > > more sensitive than 0.01D density units.  Would you be interested and
> > > able to print some of these out and measure them?  I think it would
> > > be useful information.
> >
> > Of course.  You can simply email the files to me, and I'll be more than
> > happy to print them out for you.
>
> But can you get use of a densitometer better than 0.01D ?

Of course.

Austin