Quote Originally Posted by dancqu
That ISO is for speed. For color fidelity in a gray scale
rendition, tungsten is used. Ilford, IIRC, uses 2850K.

That temperature is used because of the limitations set by
the green and red sensitisers. In other words a panchromatic
film is no faster than its green and red sensitivities.

So, for outdoor shooting don't forget your yellow filter. Dan

I'm sorry, but you've lost me on this. Could you elaborate? Are you talking about paper? If so 2850K is close to the ANSI standard. ISO 6 says that film speed can be determined using ISO sensitometric daylight, studio ungsten, or photoflood illuminants as long as the conditions are stated in the instuctions. BTW, under 5.3.4 Filters it states, "ISO speed does not apply to the filtered conditions."