Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Tyler 
Boley" <tyler@t...> wrote:
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, 
"Antonis Ricos"
> <antonisphoto@y...> wrote:
> ...
> > Otherwise, I suppose all this can be accomplished in 
Photoshop as well
> 
> Yes, it's easily accomplished in Photoshop, with the below 
caveats.
> Ernst may have some reason for doing it outside of 
Photoshop, not sure
> about that.
> Photoshop actually doesn't have full 16 bit capability. Not sure 
why,
> but all of the theoretically possible hi bit levels are not available
> in Photoshop. If you can create a true 16 bit file, as soon as you
> open it and save it in PS some levels will be thrown out, even 
with no
> editing.

Very true.  PS really only uses 15 bits internally.  The bottom
bit is dropped off.  Then when you Save it fills in a "made up"
bottom bit .  It may be mathematically irksome but makes no
practical difference.

Roy

> So if you are really picky about this, I supposed an alternative 
app
> for conversion may be usefull, particularly if you can spool it to 
the
> RIP outside of PS, as Ernst is doing.
> On the other hand, a true one channel to four channel 
conversion of a
> high bit gray original may already be less than ideal, since it 
was
> probably edited and saved in PS to begin with. Therefore the 
three new
> identical channels will also be slightly less than full. If some 
other
> method of conversion stretches the levels out a hair via noise 
or
> whatever, that's a different story.
> This is all just yakking, I doubt the difference between a hi bit 
PS
> file and a true hi bit file is worth fretting over, but it erks me a bit.
> For info on PS's idea of hi bit, see Bruce Lindbloom's site.
> Tyler