Digital BW, The Print

Hello Jeff,

>Does anyone have any recommendations on how to proceed? I'm not 
>seeing this on other images I've printed with the C86, but none 
>of the other images have such broad areas of a single tonality. 
>I've wondered whether the output file resolution is causing
>problems, and I might run that through a spline to increase the 
>resolution and see what happens. But I thought I'd check here 
>first. Thanks!

It seems typical for dither banding to show up in specific tonal
ranges.  From what I've gathered from looking at many prints from
print exchanges (it's pretty rare not to have any at all), the
specific zone can vary from one printer to another, even among the
same model. I'm not sure why this is.  I had an 870 once that always
had minor dither banding (required a glass to see it) at around Zone
III.  So one thing you might test is whether there is consistency
there.  Determining that this is or isn't the case may not gain you
anything, but it will be educational <g>.

Another avenue to explore is head alignment.  With my 2200 I
discovered that the least banding was obtained from a head alignment
number (2, meaning which line pair to choose from the print out) that
according to the instructions should not have been the optimal choice.
I just did an experiment one day and kept choosing a lower number each
time and making a print, and it kept getting better and better.  It's
almost imperceptible now.

I also get less banding with Hi Speed on, contrary to popular wisdom.
 Steve Karafyllakis was here a couple of weeks ago and I said this and
he was skeptical.  So I made two identical prints, one at each speed
setting, and let him examine them with a loupe, and sure enough, the
hi speed one was better (maybe if he reads this he'll jump in and say
something).  This may be unique to my printer...

Microbanding that is caused by a clogged nozzle looks really different
than dither banding.  It's easy to tell the difference when you look
at both examples together.

The only anomaly that I've seen respond to changing image resolution
is when there are wide bands (3/16") of light and dark running all
across the entire print.  If I remember correctly (it's only happened
twice), the bands run opposite to the direction of head travel.

I hope these will give some ideas.  I'd be interested in whatever you
find out.

Regards,
Clayton


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