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#1 Christian Tanner

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Posted 24 April 2006 - 09:44 AM

the knowledge i have of reversal stock is that it is/has:

in terms of color, more saturated (as in richer colors)
less contrast

is that true at all? ...allways the case?
and more importantly - i was wondering of its reasons.
('cause - funny enough - in my understanding on what happens with silver halides in the processing stage of color film, i think it would make more sense that a reversal film, in terms of color, is LESS saturated...). this is of course pure curiosity.

thanx for the help guys!

p.s.: also - i red the term "true speed" in releation to the
kodak ektachrome 7285 (100d)
never heard this term to be honest.
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#2 Laurent Andrieux

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Posted 24 April 2006 - 12:05 PM

less contrast


I wouldn't say so.

p.s.: also - i red the term "true speed" in releation to the
kodak ektachrome 7285 (100d)
never heard this term to be honest.


I guess it's only because there only used to be 64 and 80 Iso speed, formerly.
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#3 John Pytlak RIP

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Posted 24 April 2006 - 12:26 PM

Today's reversal camera films are designed primarily as PROJECTION CONTRAST films, that are suitable for direct projection after processing. So by their nature, they have a higher contrast (approximately 1.6 to 1.8 midscale) than a color negative film (contrast of about 0.55 to 0.60), and correspondingly less latitude. Color reversal films rely on interimage effects for most of their color correction, whereas color negative films have much of their color correction enabled by the orange-colored colored coupler masking, which Kodak pioneered in the 1940's.

Here is the characteristic curve of a typical color reversal film:

Posted Image

And a color negative film:

Posted Image

Note that a color reversal film decreases in density with increasing exposure, and has a relatively S-Shaped curve optimized for direct projection. A color negative film increases in density with increased exposure, and has a curve with a "toe" and "shoulder" with a relatively long "straight line portion", giving lots of latitude.

The curve shape of color reversal, being optimized for direct projection, will tend to compress the extreme highlights and shadows, so when printed or transferred, the "look" will be different. The different tone scale, coupled with different color correction and dyes, also gives different color reproduction, usually in the direction of a bit more harsh and contrasty.
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#4 Filip Plesha

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Posted 24 April 2006 - 01:38 PM

the knowledge i have of reversal stock is that it is/has:

in terms of color, more saturated (as in richer colors)
less contrast

is that true at all? ...allways the case?
and more importantly - i was wondering of its reasons.
('cause - funny enough - in my understanding on what happens with silver halides in the processing stage of color film, i think it would make more sense that a reversal film, in terms of color, is LESS saturated...). this is of course pure curiosity.

thanx for the help guys!

p.s.: also - i red the term "true speed" in releation to the
kodak ektachrome 7285 (100d)
never heard this term to be honest.


You can't really talk about reversal while examining one filmstock offfered by Kodak for motion pictures.

Contrast on film is higher of course because reversal is in viewing contrast, while contrast of negative has to be increased to be viewable.
The relative percieved contrast of a print vs. reversal is not that much different though (exept in case of films like 5285), but reversal has less latitude, which may not make it look contrasty, bur rather make it look like video in terms of dynamic range, in other words cut off on the edges.

E6 is only saturated if you chose a saturated emulsion, like E100VS or Velvia.
It can be more "normal" if you chose something like E100G or Astia, or compleatly natural if you chose something like Ektachrome 100 (EPN).
The saturated E6 is the trend of 90's, from early 90's to the end it seems manufacturers were compeating whose E6 film will have more color saturation. E6 films from 70's and 80's and a little more natural.
EPR (1976) is still one of the best E6 films out there in terms of getting natural colors and moderate percieved contrast.

In still film world, the only real difference between reversal and negative in prints is that you can see highlights cliping in prints made from reversal. But there are many negative films which have more saturation than the avarage E6 emulsion.
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The Slider

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