Digital BW, The Print

Hello Peter,

>why is there minor banding in darker areas only. This 
>problem only effects certain prints - depends on content. 
>Any ideas anyone.

I've seen lots of prints from just about every system in use, and they
almost all have some fine dither banding to one degree or another.  It
seems to be from a combination of the driver and the individual
printer.  

On the driver side, it always seems to be associated with certain
densities or Zones.  My theory is that the dither pattern produced by
the driver for those zones just happens to line things up in lines
rather than randomly.   It does appear to vary from one image to
another, as well, and it may have to do with the amount of grain
that's resolved in the image (if it's a scanned neg).  It seems like
the driver is trying to print the grain (or something).

As for the printer, some people report worse problems than others.  On
my 2200 I was able to reduce it by doing an alignment with a setting
of 1.  I tried every setting and that had the best result, with the
banding no longer visible without magnification.  I have seen BO
prints from two different 4000s (the 4000 has a more random dither
pattern and produces the best BO prints I've seen so far - at least
one did).  One had no dither banding and the other one had as much or
more than my 2200.  So printer alignment definitely has a part to
play.

A friend who had a 1280 couldn't make BO prints that matched my old
870 prints.  When I sold it last year, someone bought it who already
had one and wanted another.  He reported that mine made better prints
than his.  There have been many reports here in the forum of printers
that performed poorly compared to others, so they definitely vary.  

So I think it is unrealistic to hope for prints without any dither
banding.  It just seems to go with the territory.  At least for now.

Regards,
Clayton


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