Digital BW, The Print

No. 8-bits per channel does not mean the tonal range is reduced in 
any way.

8-bits per channel means you have 256 different values for 
expressing the full tonal range of each channel. 12-bits per channel 
gives you 4,096 values (most DSLRs, for example). 16-bits per 
channel means you have 65,536 possible values.

More bits per channel means the tones in your image are more 
continuous. Hence, the image is less likely to posterize when you 
edit the image. (Nonlinear changes -- such as Levels, Curves, 
Hue/Saturation adjustments, etc. -- compress parts of the histogram 
and expand others, making it more likely you will see visible 
posterization in your image where there are gaps in your histogram.

Until you start editing the image, the histogram for an 8-bit, 12-
bit, or 16-bit scan are likely to look similar. The mischief doesn't 
begin until you start editing the image. ;)

I stay in 16-bits throughout when possible, and as long as possible 
otherwise.

My RAW files are converted to a 16-bit PSD file. With Photoshop CS, 
you can do nearly everything in terms of photo editing in 16-bit. If 
you want to preserve the highest image quality, stick with 16-bits.

My master file flattens the working file, removes the alpha channels 
(necessary, if you use ImagePrint RIP), and saves it as a TIFF.

My output files for the Epson 2200 are sharpened for printed output 
and any final Curve adjustment is applied. This is when I convert to 
8-bits. Sending a 16-bit file to the Epson 2200 printer (or the 
ImagePrint RIP, in my case) gains you nothing in image quality. All 
you get is an output files that's twice the size.

So, I wind up with:

1 RAW File (12-bits, compressed)
1 or more Photoshop working files: PSD with layers and channels (12-
bits, compressed)
1 Master file: TIFF flattened and sans channels (12-bits, 
uncompressed)
1 or more Output files: TIFF (8-bits, uncompressed

If I use a RAW converter instead of Adobe Camera Raw II in PS CS, 
then I also have:

1 Converted file: TIFF (12-bits, uncompressed)

I hope this helps!

Cheers,

Mitch