Digital BW, The Print

Claude (and others),

You mention you've seen Tmax density from 3 stops to 11 stops. I've 
seen this magical 11 stops (and more) elsewhere, and recall a comment 
saying something like "this is only useful in scientific 
applications".

First, can this kind of range be obtained simply by asking a pro-lab 
to do pull-processing or is other trickery involved?

Second, how useable is such a "high-latitude" negative for a hybrid 
process? In theory, one could scan this negative with a scanner 
capable of reading a Dmax of 3.2 (about max for Tmax according to the 
datasheet), apply curves to reduce range to about 5 stops (thereby 
boosting contrast), and print. Would I be able to match the results 
of this high-latitude negative to a "normal" negative of the same 
scene, assuming the scene does not exceed the latitude of the normal 
negative?

Or (my suspicion), would the tonal range of the "high latitude" 
negative be so long as to make the scan aesthetically ugly (banding 
in dark regions)?

This topic has always been interesting to me.
-Pieris


--- In DigitalBlackandWhiteThePrint@yahoogroups.com, claudej1@a... 
wrote:
>  
> In a message dated 11/22/2004 1:52:39 PM Pacific Standard Time,  
> DigitalBlackandWhiteThePrint@yahoogroups.com writes:
> 
> From:  Steve Kale <stevekale@b...>
> Subject: Re: Digital f-stop  ranges and the print
> 
> Claude 
> 
> In the message below you seem to be  referring to more than simple
> resolution.  Do you also mean the  recordable density range?  I 
would like a
> hear a bit more on  this.  I have been spending a lot of time lately
> understanding  graduated filters better (just ordered a set - yes I 
know I
> should already  have been using them).  I would now like to 
understand how
> film f-stop  ranges equate to a) the range of f-stops that can be 
recorded on
> digital  sensor such as the 1Ds MK II and b) the density range that 
we talk
> about  for our prints (Dmax less dMin).  As I understand it one of 
the  big
> benefits of B&W film vs converted colour film is the greater tonal  
range
> that can be recorded by B&W film.  How does this range  compare 
with the new
> digital cameras?  How much of this range is  printable?
> 
> Steve
> 
> 
> 
> Boy, you have opened a big can of worms here. Most of the color 
negative  
> film (normal C-41 development) has a Contrast Index of 0.44-0.52, 
which means a  
> 1 stop luminance change in the scene records a 0.14 change in 
density in the  
> film. Assuming no major color crossovers, from a pure monochomatic 
conversion 
> of  the resultant lumped densities, you can get out to about 15 
stops of 
> luminance  before a shoulder apperars from the straight line and 
short toe of color 
> neg.  films. This from a Dmin in the shadows of about .25 to a Dmax 
of r 2.38 
> in the  highlights.
>  
> B&W films, especially Tmax (per my curve tests circa 1990) can 
vary  from 
> 3-11 stops with D-76 straight (I wild combinaton to tame I might 
add) and a  5-11 
> minute development time. So with B&W, the Contrast Index (CI) 
varies  with 
> development, as does the effective shadow thresholld speed, 
although not as  
> much as you might think.
>  
> ISO states that you need a CI of 0.65 to get the box speed rating. 
Most  
> Zoners develop their filme to a CI of 0.55 to match to the CI of #2 
paper, which  
> is a CI of 1.8 in an ideal world. So ISO essentially "pushes" the 
film a 
> little  to get their rating, but real users have always derated 
their film at least 
> 2/3  stop with their "normal development."  So, with severe speed 
derating 
> and  an extreme development "pull" you can get a lower CI than 
color neg. film, 
> which  is fixed. This could also inhibit the Dmax of the film 
depending on the 
>  developer and how it is agitated.
>  
> I have achieved densities in excess of 4.0 with Tmax developed in 
Dektol  
> (not a misprint), but I never tested for linearity.
>  
> So, the recordable density range for B&W film varies all over the 
map  and is 
> not necessarily superior to the 12 stop linear capability of some  
sensors. 
> Besides, with digital capture, you can easily increase the dynamic  
range with 
> a separate highlight and shadow range exposure to be blended later 
in  any 
> ratio you wish.
>  
> This makes blanket statements, in either case, untrue without 
specific  
> details of each method.
>  
> I prefer the speed and efficiency of digital capture with the  
> creative/corrective post processes afforded by Photoshop, but 
that's just me.  I'm too 
> impatient to go back to the darkroom for any reason. I earn my 
living  with "click 
> to print" workflows of less than 1 minute for a 4x6 color print 
from  high 
> speed dye subs, and I'm starting to do the same with Epsons, so 
maybe I've  been 
> pulled too far the other way by digital technology.
>  
> I simply love color pigments AND BO/Quad/Hex/Sept/Oct monochrome 
inkjet  
> output on various papers. What a great time to be in 
the "lightroom" with so  many 
> great choices.
>  
> My handcuffs are long gone along with my toxic chemical dependency.
>  
> Claude
> 
> 
> [Non-text portions of this message have been removed]