Variable speeds

Hey guys,
Do modern films have published daylight and tungsten speeds? Or is it a problem that was solved and now the same speed is used for both daylight and tungsten?

Thanks.

IME the speeds of b/w films are lower on anything but a clear day on either side of mid day by a few hours, and are always lower for areas that are in the shade. While it is often stated in data sheets that the box EI is for daylight, the tungsten speeds are seemingly not published any more. Yet another reason why I believe (untested) that people seem to not get enough shadow detail for their tastes. (The number one reason being that their tastes are perverted, the number two being that they don't know how to judge the quality of the light in which they are shooting and make the necessary changes in exposure, processing, and printing to match it, and the number three reason being that they don't know how to meter properly. ) Shadow areas are illuminated with mostly cool light, thus the film is slightly less sensitive to the light that is present there.

FWIW, Ilford Ortho has published daylight and tungsten speeds. Ilford probably assume that Ortho is quite likely to be shot in tungsten light, while their other films are not.

i have only 2 cents worth here...

the color temperature is measured in kelvin and has in impact in both color and bw film!

that's it, all i got!!! i'm sure i'll be further edumacated!!!

Yes they do still technically have different speeds, but a fly in the ointment is that some types of camera meter also have a similar spectral response in tungsten light so it equals out.

Ilford state the EI as Daylight. The EFKE/Adox box speeds are actually Tungsten.and the Daylight speed is faster.


#Note the films are now known by the ISO speed not DIN, KB14=KB25 etc

Ian

so if I can't find any figures for a certain film, would it be a safe bet to expose by an extra step under tungsten light? Assuming the lens hasn't got a colour filter.

It really depends on the film. The EFKE/ADOX films are less red sensitive anyway so a full stop is needed, the same goes for ortho films like Ilford Ortho Plus.

With most films the drop in film speed in "old style" Tungsten light is about a half to two thirds of a stop but there's such a wide variety of artificial light types used now that recommendations have been dropped. In addition as I mentioned before the spectral response of some light meter cells is similar to film so compensates anyway.

So best to try and see how your camera/film/meter combination works, perhaps start by giving an extra half stop.

Ian

Thanks Ian, I'm actually happy with the exposures I'm getting in and out of sunlight. I find I need a little more development time when taking photographs inside under domestic tungsten lighting, but no where near a full stop's worth. Using T-Max 400.