Digital BW, The Print

Hi Tim,

You may already be familiar with what follows but it is my experience 
and it might help someone.

This past weekend I set up an Epson 1160 with the UT inkset and the 
Niagara III CIS.

I had been using the Roark workflow MIS VM set in the 1160 for about 
a year with good results. I also print in color and BW with an Epson 
2200 driven by Image Print 5.5. I proof on Epson Enhanced Matte and I 
print my sale prints on Hahnemuhle Photo Rag. Most of my prints are 
13 X 19. I have used Convert BW Pro extensively after trying a myriad 
of other workflows. The nice thing about BW Pro is that the image is 
never converted to grayscale as far as I can tell; however, the 
image does have to be converted to grayscale at some point for Image 
Print. I have been using PS 7 Grayscale convert for this without an 
"obvious" problem.

The Roark VM workflow can posterize with subtle tonal transitions 
(skin tones) when they fall in a certain brightness range. 
Posterization is especially troublesome when an attempt at subtle 
tones is combined with a ragged histogram. Subtle tones and ragged 
histograms are mutually exclusive.

I think it is important to have a smooth histogram which is hard to 
do if one manipulates an 8 bit file to any extent. I use 16 bit files 
as far as possible. Convert BW Pro works with 16 bit files and nearly 
always produces a smooth histogram with no gaps or jags. This does 
make a noticeable difference in my work.

As an example, if I do an available light portrait in dim lighting 
with my D100  with any of the standard D100 curves the D100 produces 
an 8 bit jpeg image with a flat histogram with a lot of room at each 
end. Spreading this file to 0-255 and enhancing midtones in PS 
produces a ragged histogram and usually at least some posterization 
in the print.

To help prevent this posterization in either the VM or the UT 
workflow I do one of two things:

I create a custom curve for the D100 which takes care of this low key 
situation in-camera and spreads out the ends and pumps up the 
midtones and saves the image as an 8 bit jpeg which loads into PS 
with an excellent smooth histogram covering most of 0 -255. 
Apparently the camera uses 12 bits to manipulate before saving as 8 
bits. I then use Convert BW Pro for any needed tweeking and generally 
get a fairly smooth histogram.

I can also accomplish the same goal of a smooth histogram by shooting 
in RAW and then manipulating the RAW file and end up with a smooth 
0-255 histogram. I then transfer this file to PS and continue in 16 
bit with Convert BW Pro which almost always maintains the the very 
smooth histogram.

The UT inkset with Paul Roark's new curves for the 1160 is a marked 
improvement over the VM workflow. Now, using a file with a smooth 
histogram (as described above) and the Roark UT workflow, I can print 
an extremely low key, dark, moody portrait with excellent skin tones 
and no posterization whatsoever. I am so very happy with the Roark UT 
workflow.

Paul's generosity has allowed me to pursue high quality fine art BW 
photography when I otherwise might not have been able to do so.

Regards,

Bill Strong
-- 
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Bill Strong's Eclectic Mississippi Photo Tour
http://www.phototour.com
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>  2. A year or two ago, when the MIS Variable Mix/Variable Tone inkset
>  was the product most discussed, there were several reports of
>  posterization caused by either (a) a bug in Photoshop 7 improperly
>  converting grayscale to RGB (so some printed using PS 6), or (b) a
>  problem in using the recommended sRGB workingspace, apparently
>  resolved by using Adobe RGB (1998) notwithstanding Paul's
>  recommendation that for purposes of his curves, sRGB was the correct
>  workingspace.

That's the one reason I'm kinda hanging back - I got the posterization with
the old VM inkset on an 1160 and never did resolve it - I switched to the FS
inks instead.

I'd be interested to know if anyone who experienced the posterization in the
VM inks and switched to the Ultra-tone set has found it was either resolved
or carried over?

tim