Digital BW, The Print

> >> But how 'bout showing us some of your posterized images for our
> >> edification?
> >
> > Well, that is a problem.  You need to see prints, not web
> images...  Images
> > can look fine on the screen, but when you print them, they are
> posterized.
>
> So scan the prints.

Well, that really doesn't work either...  Seeing the prints does, so why
waste your time futzing around with anything else?  I guess I don't
understand what the problem is.  Are you saying you have NEVER had visible
posterization by making tonal corrections to your 8 bit files?

> We both know it's all image dependent, but if nobody shows what types of
> images handle abuse well and what types don't, we don't know what
> to make of
> that knowledge...

I don't know that it can be characterized...and if it can, that may take a
bit of work.  I KNOW that I used to get posterization doing tonal
corrections to 8 bit files, so now I just make sure I get my tonal
corrections done in the scanner driver, and voila!  No posterization at all
in any of my prints.  Why can't Dan (or you) just do this your self?

> The current conventional wisdom is
> that we all
> need to walk on eggshells while doing any 8-bit manipulations, when in
> reality some 99% of images do get 8-bit manipulations and do quite well by
> them.

Not at all.  It depends on WHAT you are doing, and what your images look
like, and how your scanner is set-up etc., what scanner you are using...bla
bla bla.  There are so many variables that to try to quantify this with some
exact number is a fool's errand.  I KNOW that it's far more than %1 from my
personal experience, and if I had to guess, it would be more like %75...and
I am talking about INITIAL tonal correction to a raw 8 bit file, file
derived as I've specified previously.  Now, if you are talking about just
small moves on a file that has all tones present...then it will be much much
less, of course.

> The other point is, if it's so damn difficult to demonstrate how
> the images
> fail, the failure can't be as common or critical as we are led to believe.

Well, I know I can see it in a heartbeat with my images!

> >> Remember, we only need to retain a max of about 100
> >> tones for a BW print; which means we can lose 156 out of 256.
> >
> > Actually, no.  It depends on WHAT tones you "lose" and where they are.
>
> Indeed. But think about it, some people get squirrelly if they
> see ANY gaps
> in their histogram,

And there's nothing wrong with that.  Assuring you have a full tonal range
will assure you of no posterization in most every image.  Easy, why fuss
with it?

> I'm only trying to give people some freedom here. I bet at least
> 80% of the
> people on this list do almost all their PS manipulations on 8-bit
> files,

See, that's where I think this whole subject is misleading.  Most people
don't do their initial tonal corrections on 8 bit files intentionally.
Again, the initial tonal correction is done in the scanner driver...so if
you're doing some minor correction on an 8 bit file in PS, it stands a much
higher chance of being insignificant.

> The problem with most peoples experience in this matter is that
> one day they
> work an image in 8-bits and they get a bad print. Another day they work a
> different image in 16-bits and get a good print. They conclude working all
> images in 16-bits is the fix.

How do you know that is what they did?  I doubt that.

Austin