Digital BW, The Print

The long exposure is what I use for
> B&W negative and there I see the same (not similar)
> artefacts in the shadows observed in digital HDR. Nothing
> special just Vuescan's tools

Just one comment- the artifacts you are seeing may relate to flaws
with Vuescan rather than the scanner or negative material.  I strongly
caution *against* using Vuescan's long-exposure pass (it has a new
name but does not seem improved) which has alignment issues, can
introduce halos and doesn't really reduce noise.  The free version of
Photomatix will blend two images and not apply a watermark.  The pay
versions give you more options.  I highly recommend manually scanning
(crop set to maximum, focus locked) exposing for the highlights and
shadows and blending manually or with a program like Photomatix.  I've
also heard good things about Enfuse.

This is a comparison I did a while ago:
http://www.jingai.com/vuescan2/long%20exposure%20comparison.html

The Photomatix blends are a bit mushy as I have since discovered I
need to lock focus between first and second scans.