Can you please explain the "nm" sensitivity rating for Pan films?

[Pirate]

Every time I look on the net for an explanation of the "nm" rating in film sensitivity I get links for New Mexico.

Pan Chromatic films are sensitized, I get it, but I'd like to fully understand this rating as it works for each of the colour sensitivities of the film.

Can someone please explain it or give me a proper link so I can learn more about this?

Thanks

 

[sebastel]

nm = nanometer
unit for the wavelength of light.

other useful terms for searching:
ortho, pan, superpan, spectral sensitivity, spectral response

 

[delft]

You can look at this site to see what nanometers hang out with what colours. The sensitivity-graphs you see on spec-sheets for films show the sensitivity of that film for a certain wavelength/colour. Panchromatic film, which is sensitive for blue, green and red light will have a broad bump in it's sensitivity graph from ca. 400 to 700 nm (blue to red). in this bump, some films, like Tri-X will be a bit more sensitive in the blue part (400-500 nm) and some films, like TMY will be a bit more sensitive in the yellow part.
Superpanchromatic films will extend their sensitivity a bit beyond red (past 700 nm).
Orthochromatic film is not sensitive to red (the bump goes to zero above 600 nm) and can be processed in a red safelight, but will render red lips as black.

Dirk

 

[Pirate]

Thanks, that's what I was looking for!