Filters and B&W C-41 process film

[themoleman342]

Does anyone know if colored filters have the same effect on B&W C-41 process films as they do with traditional B&W pan films?

~Marc

[A G Photography]

Filters aren't the problem with C41 BW films. They behave like they should.
(have a look at kodak T400CN official page http://www.kodak.com/global/en/professional/support/techPubs/f2350/f2350.jhtml)
Most problems I've heard of came from labs that have C41 developing machines not well tuned. A color cast while hard to notice on color film is pretty evident on black & white. But this come from the developing process, it's not on the negative itself which behaves just like any other B&W film (just with a different grain).

[themoleman342]

Can't the same thing be said for pan films that are sent to a professional lab? Or are the prints never 'corrected' through the machine? I guess I don't quite understand why the c-41 machine would automatically negate a filter effect.

[Nesster]

The color cast has to do with the auto exposure / auto wb on the machines not being able to read pure b&w... so the scans and prints tend to come out greenish or brownish etc. Sometimes I like the effect, other times I desaturate and the result is pure b&w. (then I apply my own toning, I don't believe in 'pure' b&w ever existed in nature. All photo papers had some tone, and even newspaper ink isn't necessarily pure black)

So yes, the only chance you have with the C41 B&W films to get filter effects is at the time of exposure. The results are similar to other B&W films... not necessarily precisely the same, but then one can argue that different traditional films didn't all have the same precise spectral responses either.

With color film (or most digital cameras) using color filters at exposure time is at best redunant, and more than likely will cause one of the channels to clip. With these media you apply filters and color shifts etc as you do your pp b&w conversion.

(I tried a deep red filter with a K100D Pentax. Disastrous results.)