Digital BW, The Print

Roy,

If I do as you suggest, emperically I just can't see how its going to come
out at more than 6 bits of step resolution.
This seems to be no different to using a driver like ABW that only supports
8 bits of resolution and hence with ABW you only get 256 levels from the
1024 level wedge (basically every 4 steps come out at approx same value).

Note I understand that in a continuous tone gradient of 64 levels the
dithering of the printer driver will create lots of levels and I guess I
could easily find 1024 different levels. But I have a step wedge where each
step is discrete and big enough to be measured independently by the
spectro.  I am not looking for a random set of 1024 levels, I am looking for
a specific stepping of levels of approx 0.1 L* between paper white and dmax

I think we are talking about two very different measurement scenarios, or I
completely misunderstanding what is going on.

Mike




On 19/11/06, Roy Harrington <roy@...> wrote:
>
>
> Mike,
>
> I'm really saying more than that.
>
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com<DigitalBlackandWhiteThePrint%40yahoogroups.com>,
> "Michael King"
> <drmrking@...> wrote:
> >
> > John,
> >
> > The current hardware (Epson x800) is already capable of printing a least
> 10
> > bits of gray (1024 levels) with IP (based on my own tests with a
> spectro).
>
> The point is that you can get those 1024 levels with a 6 bit file. The
> issue
> arises because people say 6 bits = 64 levels so you couldn't represent the
> 1024
> levels. This isn't the way it works. ALL possible measurements that show
> 1024 levels are averaging over an area with many pixels, so measuring more
> than 64 levels is easily done.
>
> It would be great if you could take that exact setup with IP. Take the
> file --
> I presume it's a 16 bit stepwedge -- do the Photoshop operation I
> specified
> making it only have 64 grays. I maintain the file with look the same and
> print
> the same and when you measure it you'll still get 1024 levels.
>
> >
> > Correct me if I am misquoting you Roy, but I think the point you are
> making
> > is that human vision probably struggles to perceive any difference in
> images
> > with more than 6 bits once you factor in PS dithering.
>
> Human vision will probably limit how far manufacturers will bother to
> advance.
> But my claim about # of grays is for your high end spectro, too.
>
> >
> > Certainly without the dithering I think I can percieve more than 8 bits
> > (around 9 bits) in a step wedge.
>
> I'm not sure what you would have in mind -- dithering is the ONLY way an
> inkjet
> print works. There is no other way. Dithering of the ink drops is needed
> to
> give a lot of grays in the print. The very slight dithering in PS is so
> minor
> compared to what happens in the driver/inkdrops/paper that the PS stuff is
>
> irrelevant.
>
> Roy
>
> > I'll do some more testing with dithered vs non-dithered images to see if
> > there are real world situations that the dithering doesn't handle well.
> >
> > Mike
> >
> >
> >
> >
> > On 19/11/06, john dean <deanwork2003@...> wrote:
> > >
> > > Roy,
> > >
> > > I believe I understand most of what you are describing here. It seems
> > > to confirm what you've said all along.
> > >
> > > I have two quick questions though. First, do you see the potential for
> > > sofware rip advances that WILL allow us to gain output advantage in
> > > sending bit depth larger than 8 bit to the printer in the near future?
> > > And, second, are any of the new large format 12 channel pigment
> > > machines that you've investigated addressing anything larger than 8
> > > bit capability already?
> > >
> > > I guess what I am getting at is IF a bit depth beyond 8 bit WAS
> > > possible in the near future, would we be seeing this capability coming
> > > from new software, new hardware, or a combination of the two designed
> > > in conjunction with each other.
> > >
> > > John
> > >
> > >
> > >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
> 
>


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