Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" <darkroom@i...> wrote:
> 
> 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.  

Austin,

You did write this, didn't you?
> > > > If the file only contains 256 levels of gray, and IF (BIG IF) what you claim
> > > > is true, that standard Piezo is capable of 1000 tones, where do the extra
> > > > 744 levels of gray come from? How, exactly, are they derived?

Don't Jon and I answer where the other 744 levels come from?

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.

Jon's Piezo website claims this.  I make no claim whether or not it actually
does this, because I don't know.  I only claim that your argument of 8-bit can't
make 1000 levels is flawed.

> 
> > 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.

I'm fine that you don't believe the Piezo claim.  The problem is you can't
PROVE it false mathematically.

> 
> > 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...

All either one of us can do is speculate, neither of us KNOWS whether
or not piezo can or cannot print that many grays.  The math of the
situation PROVES neither side.

The only info we really have is that the Piezo website claims 1000 grays.
Maybe Cone has measured them all, maybe he hasn't.  Maybe he calculated
it theoretically, maybe not.  Maybe it just marketing hype, maybe not.
Maybe he'd tell us which, maybe not.  Maybe we should care, maybe not.

> 
> 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.  

"HOW it may do it" doesn't prove that it does, but it does disprove the
argument that it's impossible.

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

Roy

BTW, a little aside:  I noticed on the piezo website that the claim of
2160 dpi is now qualified by the word "effectively" -- a nice addition.

Roy