Digital BW, The Print

on 5/23/02 12:20 PM, Jerry Olson wrote:

> Hi Allessandro,
> 
> Well on my images the noise in the shadows on the monitor is very
> obvious when I scan a slide in 8 bits. If you make a large tone
> adjustment in an 8 bit scan and then scan the same slide in 16 bits and
> make the same adjustment, its obvious on my monitor that the 8 bit scan
> is inferior. I don't have to make a print to prove it. Its almost always
> that noise shows up in the shadows. Also splotches, or mottle. This
> doesn't happen in 16 bit.

Jerry

I think the discussion always assumes that if one is making side by side
comparisons one is manipulating files of equal quality, just different bit
depths. You're saying your 8-files start out at a distinct disadvantage to
your 16-bit files, so naturally they'll end up worse too.

But apparently each device will capture and process data differently, so
while one device will output a superb 8-bit file another will output a lousy
one. The danger is when we make sweeping generalizations about image editing
based on a few samples from any given device.

Obviously it's true that obtaining and keeping your data in 16-bit mode as
long as possible will be safest, and so long as the data is inside the
operation of the scanner you might has well keep it in 16-bit. There would
be no quality or convenience advantage to having your scanner capture and
manipulate 8-bit data when it can just as easily do it on 16-bit data.

However, once you have a quality scanned fully toned 16-bit file, is it
advantageous to keep it in 16-bit mode to perform any and all further or
local edits, or convert it to 8-bit where it's size is smaller and Photoshop
provides a full range of tools, layers and masks? It's worth it if it shows
up on output, but not if it doesn't.

I take a hybrid approach. I scan and do global edits in 16-bit, I save that
and then dupe the file and convert the dupe to 8-bit, where I apply local
and/or finer edits. I do this in 8-bit mode because I'm a layer and layer
mask freak! I can then go back and load those 8-bit adjustments on my 16-bit
data if necessary, but it's yet to be useful to do so.

That's not to say my prints are always good, just that using ONLY 16-bit
data has yet to be a fix for what was bad!!!

Todd

PS, If I ever get involved in another bit depth discussion, someone, please
someone, shoot me. ;-)