Blue filter for recording fog.

[Mike Kennedy]

I have been checking out my filter collection and all I can find are 2 color correction (80B & KB 20).
Can I use these?

Thanks

 

[Mike Kennedy]

Should have added that I am using B&W film.

 

[AgX]

Mike,

The transmission curves of the KB20 and the 80B look quite similar; thus one could consider using either.

The main difference is all series 80 filters have a rise of transmission again in the near infrared (which should not be a problem to you), whereas the KB20 has a steep rise even just below 700nm. That means in case you are using a hyperpanchromatic film the 80B would be the better choice.

A plain blue filter as B40 has non of these rises in transmittancy, however its transmission/absorbtion ratio is not that pronounced.

 

[Mike Kennedy]

Thanks AgX,
I'll give it a try tomorrow.Hot days + Cool Nights=Fog