Digital BW, The Print

Hi,

I've been printing some digital camera (6mp dslr) pictures lately and 
they all seem to have the same problem: the shadows posterize. This 
is one problem I have not had with scanned negatives.

I dont know where this come from. Is it noise or something else ? I 
have tried some noise software but it give the picture a plasticky 
artificial look.

Workflow: Open the file in Photoshop 7 with the RAW plug-in, convert 
to 16 bits and do all other adjustements in Photoshop.

Printer: Epson 1160, UT inkset and Paul's curve.

Thank in advance,
Andre