Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" <darkroom@i...> wrote:
> 
> 
> > > I did get a response from Jon Cone on the dithering.  His comment was
> > > basically that "a dither pattern was not visually evident", and secondly
> > > that it "does not use a dither pattern in the traditional
> > sense...PiezoBW
> > > does not use static screening techniques"...
> > >
> > > He seems to want to distinguish his dithering technique from any other
> > > dithering technique...and I guess his claim is his way of doing that...
> > >
> > Austin,
> >
> > You left out the portion of his post where he said,
> >
> > "One is input (your file). One is output (the printer driver.) You are
> > thinking of an output driver only as an input translator. Where a lot of
> > these gray values go is towards averaging and smoothing (not just specific
> > tone reproduction). PiezoBW looks pretty damn good. There is a lot more to
> > PiezoBW than just translating an input value to
> > an output value."
> >
> > This is along the lines of what Tyler, myself and others have
> > been saying on
> > this thread. The driver, printer, ink and paper gives you an
> > interpretation
> > of the input file and if it give good results the technical specifics may
> > not be all that important to us.
> 
> Martin,
> 
> Sorry, but <sigh>.
> 
> It's also EXACTLY what I've been saying too...the fact that the tonality
> isn't mapped 1:1 via "dithering" is undisputable, and has never been an
> issue with me.  What Jon said didn't answer my question.
> 
> 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.

Austin,

Well I don't feel quite so bad, Jon Cone gave you the same answer as I 
did and again you missed it.   I'll try one more time.

Just so we're talking the same issue, I'll restate it:
The input file is 8-bit which means each pixel has 1 of 256 possible values.
Piezo has claimed "more than 1000 gray values".  You have repeatedly
stated that its impossible to get 1000 values from an 8-bit pixel.
Clearly you can't, but no one ever claimed you could.  The Piezo system
gray values on a print.  The only place that contains "1000 gray values"
is the print.  What can that possibly mean?  You use a densitometer of
sufficient quality and look for different values.  As you go over the whole
print if you can come up with 1000 different density numbers then the
"1000 gray values" criteria has been satisfied.  So, is this at all possible
given an 8-bit input file?  Sure, it's quite easy.  All you need is the
densitometer to be reading an area that is (as you say) derived from
4 pixels of the original file.   In going from a value 102 to a value 103,
by averaging 4 pixels you can get 102, 102.25, 102.5, 102.75, 103.
This gives you 4 gray values for each input pixel level so 
4*256 = 1024 gray values.  This is what Jon Cone meant when he said: 
 "Where a lot of these gray values go is towards averaging and smoothing."

Roy

> 
> The reason I didn't post that part of his post is because it is still
> inconclusive, and I've asked more questions of him to try to get answers to
> this.  The dithering part, I believe, he has answered as well as he's going
> to answer it.
> 
> Regards,
> 
> Austin