Digital BW, The Print

----- Original Message ----- 
From: "Tyler Boley" <tyler@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Saturday, June 07, 2003 8:58 AM
Subject: [Digital BW] Re: OPM in theory (to Martin's q.)


> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Martin Wesley" <
> mwesley250@e...> wrote:
> ...
>
> > Anyways my point is that 8-bit image adjustment is widespread and that
makes
> > data loss from poor or over adjustment an issue. So if something like
> > OPM/IJC increases the margin of error I have working in 8-bit and allows
me
> > to push the data a bit farther before print quality breaks down, I would
be
> > very interested.
>
> Well, now I'm really blowing smoke because of my lack of knowledge. How
> that linearization is applied is really the question, and if it's
> primarily the same as a final adjustment curve out, then potential
> destruction is a non-issue in terms of one method over another.

Tyler,

That makes sense. There is no free lunch and the real solution for me lies
in the hands of Adobe and wheither or not they will every provide all of the
current 8-bit functionality in 16-bit mode. I'm not going to hold my breath
on that one.
>
> > If it doesn't, then as you say, it is then a matter of ease
> > or use and convenience which can be a significant factor.
>
> Absolutely, there are many impressive characteristics of OPM/IJC, and
> if it supported my printers, I'd be all over it.
> But here's another major issue we are ignoring. Antonis tells us that
> resizing the file to a friendly dpi is ideal with OPM/IJC, as is high
> bit. If changing to 16 bit then resampling, you will be filling in
> levels and certainly be sending a file with no gaps. Purists would say
> it's non image info, or noise, but I would say it would result in a
> significantly better print than a file with major dropouts in the
> histo. So any internal tonal adjustment done by linearization will no
> doubt be non-destructive, you're working with a lot of levels now. Of
> course you could do the same thing before a final adjustment
> curve out...
Once again I agree. You could avoid data damage from applying final printing
curves by going to 16-bit before using them. This would be interesting to
try with the RGB seperation curve method. I would welcome a program that did
fill in the data in 16-bit during conversion but I suspect that is not what
is happening here. I would bet they are simply right or left justifying the
data. Otherwise the process would be pretty intense because the software
would have to decide which pixels to change from a specific value in 8-bit
to some inbetween value in 16-bit based on adjacent pixel values. That could
be a real nightmare or a blessing if done well.
>
(snip)
>
> ...You have certain input data from the scan or
> > digital capture and the order or manner in which you alter that data
from
> > its initial to final form would seem to be immaterial to the final
result.
> > (Which goes back to the importance of scanning to printing.)
> > Can we be
> > certain that all paths treat the data in the same manner?
>
>
> No, some adjustments MAY be being applied in these drivers by defining
> how they ramp, rather than simply applying a curve to an existing file.
> Also, I've found that adjustments applied via a profile conversion
> result in more loss than the exact same adjustments applied manually,
> though the difference may never show in a print.
>
(snip)
>
> Quad ink separation is very severe, no matter where or how it's
> applied. So how all these genius' are addressing that is interesting,
> it all seems to work to
> varying degrees. You can detect stepped output sometimes with some
> systems. I think that just further stresses that our files need to be
> pretty tough to begin with.

Point well taken.

So in summary it appears that IJC/OPM and QuadTone-RIP don't offer any
absolute improvement in print quality over other earlier methods. However,
they may allow the user to reach the ultimate quality level of their
printer, ink and paper more easily, which for a given user may result in a
significant improvement in their own print quality. I think both of these
programs are key advances in that they do offer the user access to
individual channel control if desired, their low cost (or no cost) and open
system model is the direction most beneficial to end users. I hope that we
will see more info on these systems as they mature.

Martin