Really? A red filter will darken blue sky exactly the same as it will darken a red apple?
Really? A red filter will darken blue sky exactly the same as it will darken a red apple?
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
Well, there are green apples too. It will darken those. "Blue" sky is a relative term. Inhabitants of LA think scudgy brown is blue. Grad filters won't accentuate the difference between blue sky and clouds like a contrast filter will because they just overall darken a whole section of the scene regardless; I never had a high opinion of grads, especially since a former resident up the hill from me with his name on a brand of them did such awful fake-looking shots with them himself; but they do make more sense in color photography than black and white.
A color contrast filter from yellow-red will darken blue skies. In extreme cases up to 3-4 stops when using a red filter and with a really saturated blue sky (often too much for my taste). A yellow filter with a milky blue sky will have a very small effect. Looking through the filters will give you an idea. Metering through the filters and comparing the blue sky reading through the filter to a neutral-colored object (grey, white) will give you a rough idea of just how much the filter will darken the sky in comparison. Granted, this is somewhat approximate, but it's better than guessing. After a while, you'll learn which filters give more or less exposure than your meter reading and learn how to compensate.
Polarizing filters often work well and it's easy to judge what you'll get just by viewing through them. Just be careful with wider lenses as the polarization across the sky is not even and a large expanse of sky may be well polarized on one side and hardly polarized at all on the other.
"Balancing" sky and foreground is often an exercise in futility. Graduated ND filters always look fake and darken any object that protrudes into the sky. Nothing worse IM-HO than a tall tree that's light and full of detail in the bottom half of the print and black and featureless in the top half...
What's wrong with light skies anyway? That's how they should be much of the time. I try to use the light as it is or come back later. Sure, I'll burn the sky in certain prints but rarely 3-4 stops worth; too much burning gives the same fake look as a graduated ND filter.
Best,
Doremus
I beg to differ...
I'm sure I could show you a few where you'd have no idea I used a GND filter. Yes trees shooting up in the sky can be problematic though.
We perceive colored skies differently than b&w film renders and especially with regard to dynamic range, so, I would posit that oftentimes a well-placed GND in certain situations will look more "true-to-life" than a straight shot.
At the end of the day the OP must try things for themselves as likely he has his own sensibilities in this regard.
I appreciate your qualifier, "well-placed" ND grad. That might be realistic with a consistent horizon line on a prarie or above an ocean surface, but imposes quite a challenge in jagged mtn and tree skylines where many people seem to want to use them.
Why assume that the grad filter is 3 or 4 stops? I agree that that is excessive and will always look weird or fake. Traditionally, the need to use a grad is typically just to reduce the dynamic range a bit. I doubt anyone needs to compress the dynamic range by 4 stops, from like 13-14 stops dynamic range to 9-10 that can fit in b&w film. Usually a 1 or 2 (tops) stops is more than sufficient (unless you have extreme conditions such shooting a sunset straight into the sun). They also make the scene more natural to the eye because of how we perceive the color of the sky. And generally one uses “soft” rather than “hard” grads — also helps with making protruding elements not obviously “darkened”.
If your shooting slide and there’s a sky, you’re almost obligated to use one as they only have 5-6 stops of dynamic range.
Finally you can dodge during printing or even easier retouching it after scanning the negative and that removes any artifacts on protruding elements, and balances the image.
I find most ND grad use a default for not knowing how to choose and use the correct film to begin with. In black and white work, mastering a film with greater linearity allows selective expansion/contraction of detail itself, and not just broad generic areas. Add to this contrast filters, VC paper, masking, etc, and you've got quite an arsenal already and no logical need to fuss around with a linear grad. With chrome film trannies, there is a very fine line between finding a tad more wiggle room in exposure and making something look fishy. There's nothing quite as annoying than seeing a brilliant sky and foreground suspiciously similar, or even worse, a reflection in a pool louder than what it's reflecting. I've spent a lot of my life outdoors intently enjoying the light, and I think it deserves respect for what it actually is, and not just cheap lipstick. All tools are meant to be used; yet, at the same time, it means that any of them are capable of abuse.
[QUOTE=Kiwi7475;1536109]Why assume that the grad filter is 3 or 4 stops?
It was an example just to illustrate the problem.
If my sky is 4 stops brighter than my foreground, I would like to bring it down to just 2 stops. That means I need to take 2 stops out of the sky.
How do you do that?
I'm gathering a yellow filter, but what I don't understand is, how many stops will a yellow filter darken the sky? 1 stop? What about a yellow orange filter? 2 stops?
I've come to this conclusion, b&w film doesn't tend to need GND filters, but instead color filters. That was confusing to me initially. But now I don't quite understand the relationship between the filter and the impact it has on the intensity of the light. I get the color shift, but not the impact.
Did you look at the B+W filter catalogue that Doremus provided a link? That or the Hoya or the Tiffen catalogue... and innumerable web sites show examples of the impact of contrast filters. Plus they cite the filter factors.
It's just basic color wheel theory, except that b&w films see color values somewhat different than we do. Nearly every situation of natural lighting can be a bit different because you're rarely dealing with pure blue or red or whatever. Even foliage greens reflect quite a bit of red light too, apparent in Fall when chlorophyll is gone and red or yellow leaves remain. So it takes some experience to realistically assess the impact of a given contrast filter on any specific scene. But if you want to get a general impression of how a deep red filter, for example, affects scene contrast, just get a pair of red glasses from someone who sells lasers, and view the world around you.
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