Re: slide vs neg

[P3D Paul Talbot <ptww@xxxxxxxxx>]

Levey has a few words to say on the subject of film contrast.  Here are
some of them:

    "Contrast" is one of those photographic trems used constantly,
  and more often than not with little (if any) notion of its meaning.

    There is more than one type of contrast in photography: tonal
  contrast, color contrast, emotional contrast, luminosity contrast,
  and so on.

He does go on to provide a comparison chart of relative overall contrast
of major slide films:

Low Contrast          Normal Contrast          High Contrast
------------          ---------------          -------------
Ek100                 Ek100HC                  Velvia
Agfa 50, RS 100+      Ek100 Plus               Fujichrome 100
Fujichrome 50         Schotchchrome 100        K64
Ek64 Pro              K25                      Polaroid Pres'n Chrome
Ek100 Pro             K200

I recall someone on the list recently stating that the Agfachromes
were no longer low contrast, so this may be an example of where the
info in the book is out of date.  This was brought up during the
concern over the "improvements" that may have been made to the new
generation of Fuji slide film.  I did not have a chance then to look
it up, but I wanted to remind those who were concerned of a post of
mine that appeared in Digest 1747, Dec. 11, 1996.  Someone had written:

>>I have an ELPH and a Kodak 3200.  I was very pleased with the 3200 I >>got last May in terms of sharpness, lack of grain,...

And I responded:

>We have to be careful what we attribute this to.  I saw an issue of >Popular Photography at the library that had an article allegedly
>comparing APS vs 35mm photo quality...of course trumpeting
>"surprising results!"  After displaying all the proof that APS
>photos are sharper, less grainy, etc., they note, almost as an
>aside, that the APS film from Fuji used a new generation film
>technology that had not yet been made available on their
>35mm films. <deleted>

Perhaps the new Sensia is merely the first 35mm film to incorporate the
newer technology used in the APS emulsions.

* * * * * * * * * * * * * * *

Levey also discusses grain, and explains that graininess "measurements"
are less than satisfactory because of the variety of things that affect
*apparent* graininess (e.g., whether the grains are arranged in a random
or orderly fashion).  However, his spec chapter (discussed in the next
post) does include measured "Diffuse RMS Granularity."  I will simply
state here that, to no one's surprise, K25 had the lowest measured RMS
(with a value of 9).

(Continued next post)

Paul Talbot


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