Digital BW, The Print

----- Original Message -----
From: "Austin Franklin" <darkroom@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Tuesday, August 20, 2002 5:56 AM
Subject: RE: [Digital BW] Dmax and drivers was Getting perfect neutral
prints from Epson 7600/9600 etc


>
> > Austin,
> >
> > I simply created a square in PS and filled it with 100% black. I printed
> > with the Piezo driver on one end of the paper then turned the paper
around
> > and printed the square again with the Epson driver on the other end. I
let
> > the print out settle for 24 hours and then took measurements. So same
> > printer, same ink, and same paper. The difference is definitely
> > greater than
> > the variability of my Spectrocam.
> >
> > Martin
>
> Martin,
>
> Thank you for describing your "experiment".  That goes a long way towards
> understanding what's going on, for me.  You didn't happen to look under a
> high powered scope to see what caused the difference?  Can you send me the
> file, and I'll try the same thing.  I have a 90x scope that I can get a
good
> look at what's going on with.
>
> I'd love to get an "explanation" for this from Jon ;-)

This is simply a different degree of ink limitation per given papersetting.
I can flood the canvas with black ink if necessary. The RIP allows that. In
a less open driver you can not control that amount but the software people
made that decision for you and the amount of black is more or less arbitrary
depending on what they think how much bleeding is allowed. Sometimes more
ink doesn't deliver more density though. It would be nice if in a given
maximum print time per square foot the black ink lay down is equally
distributed for any unit of time. The drying between each additional droplet
makes bleeding less. I don't know whether that is used to the maximum in all
drivers. Some weaving techniques will be better than others on this I guess.
Hard to see that with a microscope.
Best way is to stop a print when it isn't finished and then look how the
weaving is done. A high speed camera and slow motion projection is another
option. The Germans call that a 'Zeit Loupe'. Nice term.

Ernst