Digital BW, The Print

Even with using 16 bit scans and doing the major curve/level adj 
before switching to 8 bit, I still have a problem with posterisation 
in areas of my prints.

I have tried the same neg/scan on several paper samples I had (Royal 
Renaissance (Photo Rag), Eclipse Satine Soft & the Bright, EAM) & 
it's pretty much the same on all.

I am using MIS sepia>neutral inkset in an 1160 with Paul's curves.

In the past some have reported duplicating the background layer 
and/or combining 2 curve adjustment layers and/or adjusing the 
opacities - this is a muddle for me.

can anyone clarify this workflow or suggest another way I can try and 
beat the posterization blues

thanks
Frankg