Digital BW, The Print

Hello All,

In the August 2002 issue of the Digital Imaging Digest (which is
written by the folks at the PMA - Photo Marketing Association) they
cover quad tone printing among others and in the article they mention
Jon Cone's Piezography system.  They attribute the following quote to
someone from Cone's company:

""Unlike the Iris process, PiezographyBW does not use a dithered
pattern. It is as close to silver properties as possible.
PiezographyBW's perceived resolution is greater than the human eye. It
renders more than 1,000 gray values in 8-bit mode. The new
PiezographyBW Pro24 renders more than 4,000 gray values in 16-bit mode." 

My question - Aren't all inkjet printers required to use a dither by
definition?

If any one is interested in the entire article contact me off list .

Thanks,

Richard Cooke
rcooke@...

Hi Richard,

> ""Unlike the Iris process, PiezographyBW does not use a dithered
> pattern.

I think he is being evasive here.  Of course, they dither...and I've had
this very discussion with him, and he knows they dither.  It's like asking
someone what they don't want for dinner...you'll probably never find out
what they do want...so you can name just about every word synonymous for
"dither", but you won't pin him down to a straight answer...but the truth
is, yes, Piezo dithers.  Jon likes to make things they do sound
"magical"...it's the "artiste" in him I guess.  None of this is a slight at
all on him, as I like him a lot.

> My question - Aren't all inkjet printers required to use a dither by
> definition?

Yes, when printing images as we discuss in this email list.

> If any one is interested in the entire article contact me off list .

Yes, I am.

Regards,

Austin

and BTW...

> ... It
> renders more than 1,000 gray values in 8-bit mode.

I believe 100, not 1000...you simply can't have more than 256 values in an 8
bit byte...

> The new
> PiezographyBW Pro24 renders more than 4,000 gray values in 16-bit mode."

I don't know that is true either...as it's not the number of bits here that
matters, but the number of inks, and the ability to actually dither them to
make that many tones...haven written many dithering/halftone algorithms for
pre-press output devices, I'm very skeptical of the accuracy of this
statement.

Regards,

Austin

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" <darkroom@i...> wrote:
> and BTW...
> 
> > ... It
> > renders more than 1,000 gray values in 8-bit mode.
> 
> I believe 100, not 1000...you simply can't have more than 256 values in an 8
> bit byte...
> 
> > The new
> > PiezographyBW Pro24 renders more than 4,000 gray values in 16-bit mode."
> 
> I don't know that is true either...as it's not the number of bits here that
> matters, but the number of inks, and the ability to actually dither them to
> make that many tones...haven written many dithering/halftone algorithms for
> pre-press output devices, I'm very skeptical of the accuracy of this
> statement.

Austin, starting with a 16 bit grayscale file, then preparing it for quad printing though a RIP remaining entirely in 16 bit in 
very much the same way Piezography does for you behind the scenes, yeilds a file that has 29,037 "unique colors" (levels). 
This is determined with a cool little utility written by Bruce Linbloom.
Even after converting it to 8 bit, it reports 1,495 levels.
Keep in mind these are 4 channel files. Some of this will be lost from channel (read ink) overlap, much will be lost because 
the Epson will round off to make it's dots, some will also be lost in the texture of the paper or our inability to determine the 
way an ink/paper combo differentiates those values.
Even with all that, 4000 may not be an outrageous claim.
Tyler

Hi Tyler,

> > and BTW...
> >
> > > ... It
> > > renders more than 1,000 gray values in 8-bit mode.
> >
> > I believe 100, not 1000...you simply can't have more than 256
> values in an 8
> > bit byte...
> >
> > > The new
> > > PiezographyBW Pro24 renders more than 4,000 gray values in
> 16-bit mode."
> >
> > I don't know that is true either...as it's not the number of
> bits here that
> > matters, but the number of inks, and the ability to actually
> dither them to
> > make that many tones...haven written many dithering/halftone
> algorithms for
> > pre-press output devices, I'm very skeptical of the accuracy of this
> > statement.
>
> Austin, starting with a 16 bit grayscale file, then preparing it
> for quad printing though a RIP remaining entirely in 16 bit in
> very much the same way Piezography does for you behind the
> scenes, yeilds a file that has 29,037 "unique colors" (levels).

Well, no, 16 bits is 64k unique levels.  Anyway, that isn't relevant.  The
printer simply can not produce that many different levels, without
sacrificing overall output resolution, and besides, the human eye can
absolutely not discern them.

> This is determined with a cool little utility written by Bruce Linbloom.
> Even after converting it to 8 bit, it reports 1,495 levels.

8 bits only allows 256 levels.  It is PHYSICALLY impossible to get more than
256 levels from 8 bits.

> Keep in mind these are 4 channel files.

No, they are not.  They are B&W files.  Grayscale.  That means only ONE
channel.

> Some of this will be lost
> from channel (read ink) overlap, much will be lost because
> the Epson will round off to make it's dots, some will also be
> lost in the texture of the paper or our inability to determine the
> way an ink/paper combo differentiates those values.
> Even with all that, 4000 may not be an outrageous claim.
> Tyler

I'm going to guess you're not thinking clearly about this, since I know you
know better...

Regards,

Austin

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" <darkroom@i...> wrote:
> Hi Tyler,
> > Austin, starting with a 16 bit grayscale file, then preparing it
> > for quad printing though a RIP remaining entirely in 16 bit in
> > very much the same way Piezography does for you behind the
> > scenes, yeilds a file that has 29,037 "unique colors" (levels).
> 
> Well, no, 16 bits is 64k unique levels. 
I'm just giving you an example, from a specific file that was processed as I descibed, not the ideal. 29,037 levels was the 
reported resuly from that particular file. Also an example of how destructive separations can be, even in 16 bit.

> Anyway, that isn't relevant.  The
> printer simply can not produce that many different levels, without
> sacrificing overall output resolution,
as I said.

> and besides, the human eye can
> absolutely not discern them.
Probably not.
> 
> > This is determined with a cool little utility written by Bruce Linbloom.
> > Even after converting it to 8 bit, it reports 1,495 levels.
> 
> 8 bits only allows 256 levels.  It is PHYSICALLY impossible to get more than
> 256 levels from 8 bits.
Per channel, Austin, per channel. You started with a one channel file, it became four behind the scene.
> 
> > Keep in mind these are 4 channel files.
> 
> No, they are not.  They are B&W files.  Grayscale.  That means only ONE
> channel.
See above, and it is a four channel driver, as I am using a four channel RIP.

> I'm going to guess you're not thinking clearly about this, since I know you
> know better...
Well, I know enough to know how quad files are properly created from gray files, manually or the automatic Piezography 
way.
That doesn't mean I ever think clearly though.
Tyler

> > > This is determined with a cool little utility written by
> Bruce Linbloom.
> > > Even after converting it to 8 bit, it reports 1,495 levels.
> >
> > 8 bits only allows 256 levels.  It is PHYSICALLY impossible to
> get more than
> > 256 levels from 8 bits.
> Per channel, Austin, per channel. You started with a one channel
> file, it became four behind the scene.

So what if it's separated into four?  That doesn't add more tones, unless
it's doing something wrong!

Try making a 256 "Z" file and sending it to the printer...see if you can
discern the tones.  I believe you'll find you have a LOT of trouble above
100.

> That doesn't mean I ever think clearly though.

Somehow I doubt that...

BTW, are you sure that 1,495 isn't in base 6 or something ;-)

Regards,

Austin