It really depends on atmospheric conditions and on your definition of the word "darken" In summer we have very blue skies in inland Australia and a yellow filter can really darken the sky, closer to the ocean or in winter, when the sky isn't as blue a yellow filter will do very little.
I rarely use filters (apart from ND) and amen to your comment about heavy handed photographers with the AA sky. I think the reason the older guys really went after sky darkening was a reaction to ortho films that made blue skies white, pan films came along and they wanted all the dark skies they could get, the darker the better.
Originally Posted by jnanian
Some of these comments are basically saying anyone who drinks is an alcoholic.
A lot of good filtration is like a good haircut. No one can tell you've had one. If people are seeing portfolios full of nothing but black skies they are looking at a filter alcoholic. There are plenty of filter users that are not alcoholics. There is a lot of territory between cementing a red filter to your normal lens and being a teetotaler.
Something else that I find disturbing about filters is there seems to be a large number of people who don't know what they are for. Yes they can darken skies and increase contrast but they can also be used to cut through haze, remove glare, hide or accentuate skin blemishes and also change the relationship between colors/shades of gray. Digital shooters and even some color film shooters (surprisingly) wonder why I shoot black and white. Well there are multiple reasons including dirt cheap easy developing and enlarging. But one big draw for B&W film is the use of filters. It is something that can't be done in other mediums. Polarization is the exception. If I want to take a picture of a landscape and cut through haze I can use an orange filter, red filter, polarizer or combine. The result simply cannot be achieved without the filters. Also if I want to lighten some spring foliage while darkening the sky a bit I use a green filter. Again it really can't be done any other way. There is Photoshoping but the results are usually poorer (noise, posterization, strange digital artifacts) and of course no darkroom print :(.
The only thing I can say is people need to read about filters and then use them in various situations. You don't have to use a sledge hammer filter(s) in every situation. As markbau pointed out how dark your sky is also depends on geographic location/atmospheric conditions. I can take a picture of a landscape with an orange filter and have it look like an unfiltered picture taken in markbau's backyard. If my orange filter landscape is terrible then by definition everything marbau is taking in his geographic location is terrible at least in regards to how dark the sky is.
Seriously I am not a filter guru. As I stated before I will shoot a scene with multiple filters and sometimes no filter just to be on the safe side. If you are shooting roll film I suggest playing around with different subject matter. Filtration to me is just another tool in the workflow. I would not ignore shutter speed, aperture, focus, tripod, cable release, flash, type of film, type of developer, type of paper or paper developer. They are all tools that give you some degree of control. I have found when used appropriately filters can add a lot to a photograph. Heck even when used "inappropriately" you can end up with something nice and unique even if it is not very realistic. And just as I would not have a portfolio full of blurry, expired film, light leak, Holga images I would not have a portfolio full of black skies. Drink responsibly.
I sometimes use filters when I make portraits of people that have poor skin complexion. An orange filter might help someone with lots of skin blemishes, for example.
I don't know why everybody is so hooked up on using filters only with skies. If you're in the woods photographing foliage, really striking results can be had by using green filters. Any time you photograph flowers and want to increase contrast between two complimentary colors, color filters can come very much in handy.
Be creative with filters, use them to their strength and to improve your pictures according to how you want your photographs to look. I for one do not like the red filter sky much. Too much of the rest of the color spectrum gets rendered too damned wacky for my tastes.
Going back to the question of film, the Arista.EDU Ultra/Fomapan stuff is really more of an ortho/pan than a true panchromatic. It is very blue sensitive and somewhat deficient in red sensitivity. Don't think you'll be able to pull off that red filter sky look with it, or even get significant cloud/sky separation using a red filter.
Thanks for keeping the post on track. I agree that the Arista.EDU Ultra / Fomapan films have a tendency to produce skies that are somewhat featureless, due to their spectral sensitivity. Beautiful film for portraits, though.
Originally Posted by TheFlyingCamera
Even though it might be a little surplus information at this point, Kodak TMax 400 has spectral response that acts like a built in filter to yield tones in bright blue skies, more so than other films I've tried. But it isn't hard to capture the sky if you wanted to with Tri-X or HP5+ either.
One comes across them occasionally under the redwoods.
Originally Posted by Klainmeister
Yellow, orange and red filters lighten blue skies relative to the rest of the landscape. Just look at one's negatives -- the skies have less density (lighter!) The brightness of skies in a print will depend on how much exposure one gives the paper. Sorry could not resist.
My main filter use is a yellow filter in the Fall to darken (increase density) the representation of the yellows on the negative relative to the greens and browns...so that I can easily print them as white in the print.
The use of a yellow came up with orthochromatic films, where a blue sky had more impact on exposure than with panchromatic film.