D F , Jan 24, 2012; 04:06 a.m.
I like dark skies produced by a combo of red & polarising filters for scenics. Now that the ground is covered in snow, what effect would these two filters have on it? My guess is If I want the snow to look real, I'll have to give up the filters(filter effect) thereby rendering the sky plain(boring)...but wait...clouds are white...they stay white with these two filters so why not the snow also...? Forgive me - I'm still learning B&W.
Javi L , Jan 24, 2012; 06:55 a.m.
If you are on a high mountain the polariser will give you quite dark blue sky, specially if the sun is forming 90º with your camera axe. The elimination of reflected light lows a bit the whole contrast. If you add a red one I guess you will get a black sky and high contrast. I would definitely pull the development.
When I print white snow I feel I need to give it a little burn with the 4# filter. Hope you can figure out the proper exposition though!
Arthur Plumpton 
, Jan 24, 2012; 10:23 a.m.
I think you are right in suppposing that the colour filters will not appreciably change the snow rendition, at least under most daytime light (early morning and late afternoon may be slightly different, given the warmer colour temperature). I find that the presence of snow doesn't really change the effect of my orange or red filters with black and white film. Getting proper snow exposure is a challenge with auto exposure cameras, given that the meter wants to render the snow as an average 18% (or 12% in some cameras) reflectance yielding a grey tone. By overriding the autoexposure and opening up your f stop by about 1 stop or more to provide white snow with detail, you might be lightening the red filtered dark sky a little. Despite their increased effect, you need to consider the potential image degrading effect of using two filters rather than one over your lens. In landscapes, where good detail is often needed, this might be important. Using a dark red filter, rather than a light red or medium red filter, might work best.
Murray Kelly , Jan 24, 2012; 10:46 a.m.
Arthur, we don't have a lot of snow here by the South Pacific (Brisbane) but beach scenes (which are similar) need a stop down usually. Sunny 16 is sunny 22. One could set the film speed to double with a p&S if the camera allows it.
I agree about the amount of glass in front of a lens, but needs must when the devil drives, as the saying goes! :-)
As an aside, yours is the first mention I have seen in ages about the gray card being 12% and not 18% - even AA was hard to convince, I have read.
Curt Wiler
, Jan 24, 2012; 11:21 a.m.
@Murray - the comment was about camera meter calibration, not the gray card reflectivity. The accepted standard for that is 18% and always has been. Meters are a different matter. Unfortunately this reflectance number keeps coming up when it really isn't necessary. Just saying "medium gray" would suffice.
Arthur Plumpton 
, Jan 24, 2012; 01:33 p.m.
Murray, I may be slow, but is that the same AA that might object to an 18% Port versus a 12% Burgundy (or Aussie Pinot?). Understand the beach question: I have some B&W sand dune fence prints from a Virginia US vacation that my Canadian compatriots regularly interpret as local snow fences.
Clay L , Jan 24, 2012; 03:18 p.m.
For snow and beach sand try an orange filter.
Best regards,
/Clay
Paul Hoyt , Jan 24, 2012; 10:55 p.m.
A polarizer can reduce reflections in snow which can compress the scale and lead to a drab photograph; you can lose a feeling of substance, snow is light and fluffy. If you over use contrast filters, the sky can be reduced to a very dark grey, almost black, and the shadows in the snow become too dark; a Yellow (K2) or minus blue (#12) are good filters to render snow with conviction and create contrast between the snow and sky.
Paul
Loren Sattler , Jan 24, 2012; 11:25 p.m.
I have had the best luck using a K2 Yellow filter,and pulling development approximately 15% from my standard when shooting snow scenes in bright sunlight. My standard for medium contrast light is Tri-X 400 rated at ASA 200, D76 1:1 for 8:15 minutes with 6 rapid tank inversions (5 seconds total) every 30 seconds. For bright, contrasty light (such as bright sun on snow) I reduce this to about 7 minutes. Negatives print well on #1-1/2 to #2 contrast filters with a condenser enlarger.
I have not had such pleasing results with a red filter. I believe it may pull too much of the blue light from the snow, but I am really not certain why. The yellow filter may not make the sky as striking (if there are clouds), but the snow can be very alive.
Hope this helps.
Loren Sattler , Jan 24, 2012; 11:25 p.m.
I have had the best luck using a K2 Yellow filter,and pulling development approximately 15% from my standard when shooting snow scenes in bright sunlight. My standard for medium contrast light is Tri-X 400 rated at ASA 200, D76 1:1 for 8:15 minutes with 6 rapid tank inversions (5 seconds total) every 30 seconds. For bright, contrasty light (such as bright sun on snow) I reduce this to about 7 minutes. Negatives print well on #1-1/2 to #2 contrast filters with a condenser enlarger.
I have not had such pleasing results with a red filter. I believe it may pull too much of the blue light from the snow, but I am really not certain why. The yellow filter may not make the sky as striking (if there are clouds), but the snow can be very alive.
Hope this helps.