Digital BW, The Print

Ok so I must confess that this and the other responses blew straight over my
head, not being a zone guy and not understanding film shoulders and toes.
Can I ask some basic questions so that I can follow the discussion:

1)  You speak of 15 stops from colour negative film.  I have heard people
saying that Velvia slide film has just +/- 1 2/3 stops, or 3 1/3 stops, of
workable range.  Are these measurements of the same thing?  (What is the
tonal range of Provia?)

2) How does one convert stops to density? Loosely.  For example, if a
scanner has a rated dMax of 4.8 how does that relate to the tonal range in
stops of film that it is going to scan?

3) Where does the "12 stop linear capability of some censors" come from?
What is the figure for the 1Ds MK II or 1Ds?

4) I think I understand the importance of linearity - kind-of-sort-of - from
printing.  Is this a similar concept? Ie evenly distributed tonal range?

5) At the end of the day we are severely constrained by the tonal range
capability of our printing.  Hogarth mentioned 8 stops for silver gelatin
paper.  How do I relate a linearised print of a step wedge on HPR with a
paper white dMin of .04 and a best black dMax of 1.68 to these figures?
(Wouldn't it be nice if they all used the same scale?)

While the boundaries of the digital print are expanding, I guess we still
need to shoot by compressing the tonal range of the scene with ND filters
(or multiple exposures) so that it can be rendered well in the print -
traditional or inkjet.  I am trying to relate the two (and the steps that
may be in between eg scanning) so that when I get out my spot meter I am not
only thinking in terms of stops but also in terms of my printer's tonal
range.  Sorry if these are basic questions but I think it will help a lot of
people tie all the talk of dMax back to the camera itself.


Thanks

Steve

PS:  this was not meant to be a digital capture vs film capture discussion -
I think the topic relates to both. I do believe there are significant
workflow efficiencies with digital cameras and I am about to make the switch
but relating the tonal range of a scene as measured by a spot meter in
f-stops back to the tonal range of the printer, ink and paper combination
applies to both forms of capture.


> From: <claudej1@...>
> 
> 
> 
> 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]
> 
> 
> 
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