Digital BW, The Print

Hello Derek,

>A little bit of computer science here...
>Converting from 8 to 16 bit simply maps those original 256 tones 
>into the 65536 space...
>There are other issues with 8 vs 16 bit related to rounding errors 
>also.

Thanks very much, it makes good sense.


>The scenario I've described above leads to the posterization that we
>see when making large adjustments in 8-bit files...

As I mentioned before, I did see in a large smooth area containing
subtle transitions some negative affects that went away in the 16-bit
version.  It convinced me that there is some merit to the technique,
at least for smooth tone areas.


>With all that said, I rarely change my 8-bit files to 16-bit before
>editing. I would only do so if there was something really wrong with
>my exposure and I needed to make large adjustments to the file.

Since I don't know beforehand what sorts of manipulations I'll be
doing, I change to 16-bit any file I'm going to convert to grayscale
for a BW print.  The added file size for me is a small price to pay
for the insurance of "overhead" if it's needed (and because it's
grayscale it actually ends up being 1/3 smaller than the 8-bit color
version).  

I use the pocket cam frequently for various things and occasionally
find an image that's worthy of a print.  It's already at a
disadvantage not being RAW, so I want to give it all the help I can.

Thanks for the good explanation.


Regards,
Clayton


Info on black and white digital printing at    
http://www.cjcom.net/digiprnarts.htm