[pure-silver] Re: Shoulder and highlight

----- Original Message ----- 
From: "DarkroomMagic" <info@xxxxxxxxxxxxxxxx>
To: "PureSilverNew" <pure-silver@xxxxxxxxxxxxx>
Sent: Friday, December 31, 2004 4:46 PM
Subject: [pure-silver] Re: Shoulder and highlight


>I don't think this is correct.
>
> Image gradation, and consequently, every final print tone 
> depends purely on
> the combination of film and paper characteristics. This is 
> best visualized
> in the typical tonal reproduction cycle, where one 
> quadrant is occupied by
> the film and another by the paper characteristic curves.
>
> A film with a mid-tone 'hump' will make for lighter 
> mid-tones in the final
> print than a straight-line film characteristic on the same 
> paper (Tmax is
> such an example). This means two films with similar 
> highlight
> characteristics can have quite different mid-tone 
> characteristics.
>
>
>
>
>
> Regards
>
>
>
> Ralph W. Lambrecht
>
>
>
>
> On 12/31/04 10:37 PM, "Ryuji Suzuki" <rs@xxxxxxxxxxxxxxx> 
> wrote:
>
>> Due to a fundamental principle of calculus of continuous
>> functions, films with vigorous highlight contrast results 
>> in darker
>> midtones if you try to print on the same paper with the 
>> same average
>> gradient and density range.
>
   A good comparison is Tri-X Pan Professional sheet film 
(ISO-320) compared to 400T-Max. Tri-X has a constantly 
rising curve, essentially all toe, intended to produce very 
bright highlights. 100 and 400T-Max are essentially straight 
line films. For the same shadow and highlight points Tri-X 
will reproduce the mid tones darker than T-Max or other 
straight line films. This can be desirable for some subjects 
but I find the straight line film more suitable for general 
use.
  From Kodak's published curves it appears that T-Max RS and 
Xtol produce more nearly straight line curves from T-Max 
films than does D-76. Fuji Acros also appears from its 
published data to be a straight line film with a small toe 
area.
   High flare lenses will produce an effect similar to a 
long toe on the film.
   Printing papers also have curves that vary from one to 
another but the effects are, of course, reversed. A long toe 
paper will compress the highlights and tend to make the mid 
tones brighter.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx 

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