Jump to content


Photo

T and D sensitivity for B&W film stock?


  • Please log in to reply
4 replies to this topic

#1 Christian Schonberger

Christian Schonberger
  • Basic Members
  • PipPipPip
  • 175 posts
  • Sound Department
  • Lisbon

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

 

 


  • 0

#2 Dirk DeJonghe

Dirk DeJonghe
  • Basic Members
  • PipPipPipPip
  • 605 posts
  • Industry Rep
  • Kortrijk,Belgium

Posted 27 March 2016 - 10:45 AM

Yes, colour temperature influences the sensitivity.


  • 0

#3 Christian Schonberger

Christian Schonberger
  • Basic Members
  • PipPipPip
  • 175 posts
  • Sound Department
  • Lisbon

Posted 27 March 2016 - 11:16 AM

Yes, colour temperature influences the sensitivity.

Thanks for the information. That explains it.

 

Christian


  • 0

#4 Mark Dunn

Mark Dunn
  • Basic Members
  • PipPipPipPip
  • 2342 posts
  • Other
  • London

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.


  • 1

#5 Christian Schonberger

Christian Schonberger
  • Basic Members
  • PipPipPip
  • 175 posts
  • Sound Department
  • Lisbon

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


  • 0


Wooden Camera

Paralinx LLC

Visual Products

Ritter Battery

CineTape

Rig Wheels Passport

rebotnix Technologies

FJS International, LLC

Willys Widgets

Abel Cine

Glidecam

CineLab

Aerial Filmworks

Media Blackout - Custom Cables and AKS

Metropolis Post

Gamma Ray Digital Inc

The Slider

Technodolly

Broadcast Solutions Inc

Tai Audio

Aerial Filmworks

Gamma Ray Digital Inc

Wooden Camera

Rig Wheels Passport

Willys Widgets

Media Blackout - Custom Cables and AKS

rebotnix Technologies

The Slider

Tai Audio

Technodolly

Paralinx LLC

Visual Products

CineLab

Glidecam

Ritter Battery

Broadcast Solutions Inc

FJS International, LLC

CineTape

Abel Cine

Metropolis Post