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Re: [OM] The perfect chrome film

Subject: Re: [OM] The perfect chrome film
From: "John A. Lind" <jlind@xxxxxxxxxxxx>
Date: Sat, 14 Sep 2002 12:29:46 -0500
At 10:42 9/14/02, Bill Pearce wrote:
I think I'm going to get seriously flamed by the Kodachrome people, but
there isn't a single perfect film. Film is a tool, you must use the tool
best suited for the job, just as a painter uses different brushes.

Not by me. I agree with your observation that no single film can "do it all." Selection should be dictated by the user based on what the user has visualized for the finished photograph and which film matches that best, both artistically and technically (i.e., archival longevity, print materials desired [if any], etc.).

I generally prefer Fuji chromes. As an all around chrome, the Provias are a
close to a universal film as we have today. The grain is finer that any
other, and the saturation is only bumped a little (note that enhanced
saturation is currently in vogue. We shall see if it remains so.).
[snip]

Two points about Provia 100F and Kodachrome 64:
Don't misinterpret this as a "flame" defending Kodachrome. I currently use both Kodachrome and Provia 100F. They're observations about two specific character traits that emerged in using them. I agree with you about saturation and Kodachrome processing difficulties in general, although I'm not experiencing them. The 7-day turn-around is not perceived as a difficulty; it's a very reliable 7 days, occasionally 5 or 6.

(1) A flaw exists with the Fujichromes that exhibits itself in specific situations. It is most prevalent in night photographs containing very bright man-made light sources in which the emulsion itself appears to flare around bright and close light sources; they need not be "pinpoint" in the image. Among those most vocal about this effect are those that routinely photograph rail engines with their very bright headlamps. I've seen it very pronounced in night street scenes with street lamps and traffic signals, especially in the foreground. Kodachrome 64 and the Ektachromes I've used do not behave this way under the same circumstances. I have not studied the cause thoroughly. The WAG I would use as a direction to head with one would investigate flare of light laterally across the emulsion caused by reflection between all the film layers; similar to index of refraction mismatch effects deliberately used to transmit light through "light pipes" and fiber optics.

(2) Grain is only part of the story for "apparent sharpness." Indeed, Provia 100F is the finest grained chrome I'm aware of. However, ultra-fine grain alone does not guarantee apparent sharpness (acuity). It also requires high edge definition which is significantly affected by emulsion thickness. Kodachrome 64 excels beyond any other current chrome film in edge definition for this reason. Provia 100F compensates for this with slightly finer granularity. It's why Kodachrome has acuity equal to or exceeding that of Provia 100F in spite of larger granularity figures. Part of this tale is revealed in the MTF curves for contrast exhibited within the mid-range of line pairs per millimeter.

-- John


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