Digital BW, The Print

I wonder what the histogram of this photo looked like before Austin expanded
levels in his scanner software?  Is there any blotchiness in the shadows in
the neg?
----------------------
Robert Morrison
rmorrison@...

310-397-2704

4131 Bledsoe Ave.
Los Angeles, CA 90066


Robert


On 5/28/02 10:44 AM, "Todd Flashner" <tflash@...> wrote:

> 
> In the "8x16 bits and BW" thread I suggested it's possible that the
> posterization we sometimes see in our prints, contrary to conventional
> wisdom, may NOT be from "overworking a file", "breaking an image",
> "insufficient bit depth", "lost tones",  or any of the various expressions
> used to suggest a problem that may occur from editing 8-bit files.
> 
> Austin has recently sent me Piezo prints for my perusal, as I am interested
> in assessing that output, being the longtime Roark/MIS user I am. He has
> graciously allowed me to scan and post an example that SUBTLY illustrates
> the type of phenomenon I referred to. I've also encountered it in my
> workflow and it has stymied me because 16-bit evidence did not help.
> 
> It's perfect this print comes from Austin because he does no 8-bit editing,
> and his histograms have no gaps within their endpoints. As such, any
> posterization in the image could not be due to the "lost tones" associated
> with 8-bit image manipulation. Furthermore, Austin's workflow excludes some
> of the other usual suspects, like interpolation, USM, or selections/masking.
> If there is such a thing as Certified Organic files that's what Austin
> prints from. So what we have is a nice print of a lovely image and what I
> will point to is not meant as a criticism of any kind - on the contrary, I
> think it may be so common that, to many of us, it goes unnoticed.
> 
> I'm posting two samples of a scan of Austin's print, one a small jpeg of the
> overall photo, and the other, a TIFF detail of the area in question. The
> print was scanned in grayscale mode at 300dpi on my Umax Powerlook III.
> 
> The files are in the Message Related folder for 5/02. Hopefully this link
> will get you there:
> 
> <http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint/files/Message%20
> Related%20Files/05_2002%20uploads/>
> 
> What I am addressing are the deep 3/4 tones along the right side of the
> woman's body. They extend from her armpit to her leg, and from the the
> bottom of her forearm to her hand. To my eyes the transition between tones
> in those areas is harsher and more abrupt than other tones in the print, and
> just have an unnatural appearance to me. I'd say the main characteristic is
> an area of mostly "flat" shadow tones which are "blocky" at their perimeter.
> 
> Whatever it is, I suspect many of us experience it and refer to it as
> posterization. My sense is the effect looks more prominent in print than on
> screen. It's possible, but I have not measured it, that the ink color for
> that ink position is "cooler" than the other inks, which causes it to stand
> out against them, but since these scans originated in grayscale mode they
> would not reveal that.
> 
> I'm interested to know:
> 
> A) Do these tones look "natural" to you? Am I suggesting there is a problem
> where none really exists? (FWIW, Austin knew immediately what I was
> referring to when I mentioned it, so if you do feel I'm making something
> from nothing it's possible that it is more evident in the print than on the
> monitor.)
> 
> B) If not "natural", do these tones look typical to you? IOW, do you get
> them with your workflow and materials? Conventional materials, or digital
> only? At what stage of the process do they appear in your work, ie, in the
> neg, scan, or print?
> 
> C) Do you notice them using some materials or workflows more than others?
> 
> My suspicion is that those areas in a well printed glossy silver print would
> have a much smoother feel/gradation, or a more natural placement of values.
> I'm guessing that those tonal transitions are somewhat present in the
> negative but are exacerbated by scanning, and then further amplified in
> printing. But that's just my hunch, I'd like to hear what others think.
> 
> This print was produced with the Piezo driver using Piezo inks, by an
> experienced user. The Piezo product is considered my some to be the "gold
> standard" for smooth output and tonality, so how likely is it to be an
> effect of that process? I don't know what profile Austin used (for what I
> believe is Epson HeavyWeight Matte), but I do know his step wedges and
> Tyler's Zees prints looked smooth and uniform.
> 
> One suspicion of mine is that this might be an effect off CCD scans. In the
> small sampling of drum scans I've had made for my negatives (thanks Mike K)
> I believe that the drum scanner handled such tones slightly better than my
> Leaf. Have any of you who've used both CCD and drum scanners noticed this
> occurrence more in scans from one scanner type over the other? The Leaf
> scans in 14-bits, same as most drums, so I don't think it's bit depth
> related, but, could the the sensor element, lens/aperture, or light source
> make a difference? Or, could this be a function of "grain aliasing" showing
> more prominently in those tones than others? I ask because their boundary
> seems blockier than other areas. On the other hand, it may just appear that
> way because the tonal transition is more abrupt, giving higher contrast at
> the perimeter.
> 
> Could it be a function of too much separation of tones? IOW, is this
> information in the "toe" of the film's response curve and, as such, flat or
> compressed to begin with? In a silver print might get this area get further
> compressed into dark shadow and print much darker, and therefore go
> unnoticed? (I tend to think not since with my images I get the same effect
> in dark sky image areas of my MIS prints, but on silver papers these tones
> print with smooth, subtle, gradations).
> 
> Obviously, I have more questions than answers. I believe this type of
> posterization (and/or whatever this is) is a somewhat common component of
> digital printing that was rather uncommon in conventional printing.
> Unfortunately, it's not always easy to determine where it comes from.
> Sometimes it's from overworking an 8-bit file, but I suspect, as often as
> not, it's from something else. I'm interested to hear what some of you think
> that "else" may be...
> 
> Todd Flashner
> 
> 
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