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T and D sensitivity for B&W film stock?


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#1 Christian Schonberger

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Posted 27 March 2016 - 09:43 AM

Hello group,

 

Just one Q: why are there two different ASA values for black and white film stock (tungsten and daylight)? I understand that for color film stock since filters are used (either 80A or 85, both taking away light), but what about black and white? Is it the color temperature (say: 3200 vs. 5000-ish Kelvin) that directly affects the sensitivity/film speed?

 

Any reply appreciated,

Christian

 

 


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#2 Dirk DeJonghe

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Posted 27 March 2016 - 10:45 AM

Yes, colour temperature influences the sensitivity.


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#3 Christian Schonberger

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Posted 27 March 2016 - 11:16 AM

Yes, colour temperature influences the sensitivity.

Thanks for the information. That explains it.

 

Christian


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#4 Mark Dunn

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Posted 27 March 2016 - 11:59 AM

Tungsten light is redder. B/W panchromatic film is a bit less sensitive to red so the speed is reduced by about 1/3 stop.

Before the 1920s film was almost insensitive to red (orthochromatic). Pan was a great advance in the rendering of skin tones.


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#5 Christian Schonberger

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Posted 27 March 2016 - 01:21 PM

Tungsten light is redder. B/W panchromatic film is a bit less sensitive to red so the speed is reduced by about 1/3 stop.

Before the 1920s film was almost insensitive to red (orthochromatic). Pan was a great advance in the rendering of skin tones.

Thanks Mark. Yep, I remember panchromatic B/W film from the old days of photography (a few of my friends had their own labs at home) and the use of color filters to dramatically change the result. I prefer color film stock for motion pictures I am planning on. I do like fine grain B/W though - for example to make the (motion) film equivalent of fine art photography. Never found anything except test or unfinished footage though - and a Super 8mm film (shot on Canon double Super8 - surprisingly clean, sharp and steady) that won a Super 8mm short film contest way back in 1981, projected with a Bauer T 610. B/W also still pops up in music videos here and there. For some reason always in slow songs. Perhaps because it is more suitable to establish a certain mood (or period feel) and to focus on textures and lighting as opposed to fast moving subjects....

 

Cheers,

Christian


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