Digital BW, The Print

Bob,

Glad to hear you are up and running with the 1280.

What you are experiencing as "solarization" we usually refer to as
"posterization". Neither term is quite correct since it is rare to see a
full reversal of tones. Generally it is a case of tonally flat areas in the
image where there should be varying tones.

Are you working in 8-bit or 16-bit mode?

The most common cause is overworking an image in 8-bit mode. Large
adjustments cause a loss of information which can degrade the image. Check
the histogram of you problem image. If there are large gaps and/or spikes in
the data (called the "fingers of death") that is a likely source of your
problem. Some degradation of the image data seems to be fine and does not
show up in the print. Other times it is deadly but does not show up on
screen.

This is particularly true of the VM workflow with the application of RGB
separation curves. In order to partition the inks properly the curves are
often extreme. Check your histogram before and after applying the curves to
see what I mean.

Solutions can consist of making as many adjustments as possible in 16-bit
mode before switching to 8-bit or staying in 16-bit all the way. Try
different curves as you have done. Some images will do better with one curve
than another. There is another set of curves for the 1280 and VM inks that
were done by Tyler Boley. You can find them in the Files section of the
group homepage in folder:

Files > Ink Sets > MIS > MIS Variable Mix > 1280 PC MIS VM

Note that these curves use different settings in the Epson driver than
Paul's curves.

The other problem area is the scan itself. Print the scan file before you do
any manipulation and see how it prints.

Crude but sometime workable fix is to select the area or tonal range that is
giving you problems and apply a curve adjustment to increase the contrast. A
last resort.

Martin Wesley

http://www.borderless-photos.de/guests.html



----- Original Message -----
From: "daintreeriver2002" <workmantx@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Friday, August 02, 2002 12:03 PM
Subject: [Digital BW] Solarization Problems using MIS VM Quatone Inks and
Paul Roark's Curves


> I just got going with my new MIS VM quadtone inks and EAM paper early
> this week.  My first attempt, on Monday, using a scanned negative (as
> a positive) and using Paul's Medium Warm curve for the Epson 1280
> worked great.  No banding, no solarization, great tonal range.  I'm
> really excited by the possibilites.
>
> Since this first print, though, I've been having troubles.  This
> morning, I actually converted a color digital image and played with
> the channel mixers in doing so.  The image looks great on the
> monitor.  Lots of information and texture in all parts of the image.
> When I use the medium warm curve, though,  my bushes and background
> landscape areas are solarized and have significant loss of detail.
> Trying again, with the neutral curve, the bushes are now fine, but
> I've lost an incredible amount of detail on my building's brick
> wall.  Plus the smidge of landscape in the background still looks
> odd -- almost printed as flat tone.  (I've also had similar
> solarization problems with another scanned negative, though, where I
> printed it before and after adjusting the curves in selected areas.
> On this one as well, I was using the Medium Warm curve.)
>
> Does anyone have any ideas about what my problem may be?  I'm using
> preload cartridges from MIS.  Is it possible that too much ink is
> coming out of some of the toner slots and not enough out of other?  I
> followed Paul's workflow steps very carefully, so I don't think I set
> something up wrong.
>
> Thanks in advance.
>
> Bob
>
>
>
>
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