Achieving maximum/extreme sky to cloud contrast in black and white photography?

[l2oBiN]

I would like to know how one can create extreme sky contrast in cloud to clear sky?

I am aware of the red filter, but are there even more effective ways to getting the contrast? I am looking for an even more extreme effect with maximum cloud separation...

[Scott Walker]

Use a red filter and if the subject matter allows it you can print on MG paper at grade 2 or whatever then burn the sky in with a grade 5 filter in place.
It takes some practice and not all scenes work.
The results are a bit surreal but pretty cool none the less.
If you scan & print that way I'm sure it is much easier with photoshop but I can't help you there.

[Peter Gomena]

Red filter + polarizer if it's the right angle to the sun.

Red filter + underexpose one stop and increase development to "pop" the clouds back up to higher zones.

There are varying degrees of red filter, too, the 23A light red, 25 red, and 29 deep red, which yields more sky/cloud separation yet.

Peter Gomena

[SMBooth]

Ilford SFX200 film with red or IR72 filter.

[uphereinmytree]

just darken it in photoshop (just kidding)

[J. Fada]

Add a polarizer before the red filter as Peter suggested above. I put the polarizer in front of the red filter.

The other alternative is to go to the Desert Southwest or extreme elevations. You won't have the problem in those places.

[Maris Rusis]

Please excuse the medium format but infrared film behind an infrared filter can exaggerate clouds.

Tree and Cloud, Lake Cootharaba

Gelatin-silver photograph on Freestyle Private Reserve VC FB photographic paper, image size 16.4cm X 16.4cm, from an Efke IR820 negative exposed in a Seagull 4A 103A twin lens reflex camera fitted with an IR720 filter.

[polyglot]

For the most extreme black-sky effect, use an IR film (e.g. Efke IR820) and an R72 filter. For example (not LF): 1, 2, 3, 4.

[Jim Jones]

Contrast between clouds and blue sky, and within clouds, was enhanced by using very contrasty film like the late Kodak Tech Pan developed in print developer or whatever gave adequate contrast, but often shadow detail in the foreground was lost. Dodging the foreground during exposure can help this somewhat.