Digital BW, The Print

Roy,

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

No, Roy, I did not miss "it".  What you and Jon said, I knew long before you
two said it.  What's interesting is that you both are not answering my
questions.  You are off on a tangent that people already understand and is
not in dispute.  Yes, the output does not match the input 1:1, and YES it is
THEORETICALLY possible to produce INFINITE tones with only 1 ink, and I've
said this way early in the discussion.  That all doesn't mean that the Piezo
does in fact print 1000 tones though.

> 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.

And that is what I simply don't believe...that there are 1000 different
density values on a print, that are intentionally printed by the Piezo
software/ink combination etc.  I don't believe it's been measured as such
either.  If it has, then so be it...but until someone actually says they
have done it, and they have physically identified 1000 different tones, I
simply do not believe it is possible from Piezo.

> So, is this at
> all possible
> given an 8-bit input file?  Sure, it's quite easy.

Theoretically it is possible, but practically it is not, as far as I am
concerned.

> 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.

I know what you are saying, but I simply do not believe it is capable of
working that way.  I don't believe you know exactly how many tones Piezo
prints and how it prints them, you're speculating...but you're also giving
examples that have already been discussed, and don't answer the real
questions.  I'm not saying you're wrong...but it is still speculation...

I'll repeat it here as simply as I can, so you don't misunderstand
this...again.  I understand that there is not a 1:1 input vs output with
dithered printing...as I've written many dither algorithms and designed
dithering hardware.  I completely understand how dithering works.  I
understand that theoretically you can get 1000 tones from a dithered
printing system...given enough area, small enough dot sizes, and enough
different tones of ink...and/or combinations of these.  I understand all
that, and have always throughout this conversation understood that.

What I don't believe is that the system is actually practically capable of
it.  Plain and simple.  Any amount of speculation as to HOW it does it
doesn't answer the question.  Showing a print that shows 1000 discernable
tones...like 1000 1/2"x1/2" blocks...not simply a gradient, that will mask
the systems abilities, since you will not be measuring individual tones, but
multiple tones at once, therefore giving you the impression of it producing
more tones than it does.

Austin