B&W filter for from tall buildin

[Richard Wasserman]

I am going to be photographing from the roof of Willis Tower in Chicago which is at 1,451 feet using 4x5 FP-4+. Chicago tends to be hazy, especially this time of year when the humidity is high. How should I filter these exposures to cut through as much of the haze as possible? Does a polarizer do anything to help?

[Gem Singer]

With B&W film, a #15 (yellow-orange) or a # 21 (Orange) filter should do the job.

[Walter Calahan]

Or a #25 red. I'd try all three.

[chris_4622]

Richard,

When I was up there, 90th floor rooftop, with Michael he used a light yellow. If the haze was particularly bad he added a UV 2E as I recall. This was in October, not like the summer we've been having.

chris

[Mark Sampson]

I'd second the idea of trying several different filters. You'll find that one of them will give results you like better than the others... and it may not be the one you think. Shoot one holder unfiltered to provide a baseline, too. I'd also consider shooting a series for normal development and another for N+1, to deal with the contrast loss inherent when shooting through miles of air. Film is cheap and opportunities like this can be hard to come by.

[rdenney]

It depends on what is making the haze. If it is ultraviolet bouncing off vapor, then the yellow-to-red filters will filter that out. But if the haze is caused by dust, that may not help that much. I had trouble photographing distant scenes in Las Vegas making decidedly non-artistic photographs for evaluating line-of-sight for microwave towers. It was dusty that day, and the dust was the typical red sand prevalent in that area. Red filtration didn't work--it made it worse by lightening the light reflecting from the red dust. Blue actually did the best, but there there is little water vapor there to reflect UV.

In another non-artistic photographic effort, I made some pictures of traffic flow from the 64th floor of Transco Tower in Houston a few decades back. The windows of that building are tinted blue to minimize heat gain from infrared, and I found this actually improved clarity for pictures pointed down, but did little for UV-rich views of the horizon.

And I would also try a polarizer, which will eliminate reflections from vapor coming from certain directions.

In short, bring every filter you own.

Rick "often surprised by atmospheric haze" Denney

[Richard Wasserman]

Thanks everyone. I'll take the advice and bring a lot of film and use several different filters in various permutations (seems kind of obvious in retrospect). I don't know what the haze really is, but assume it's a combination of high humidity and smog–yummy!

[patrickjames]

I would suggest using infrared film.

[Brian C. Miller]

For moisture, I also recommend IR film. This stuff can't be beat when it comes to cutting through normal atmospheric haze! If you want mountains 60 miles away to look sharp and clear, infrared film is it!

[Richard Wasserman]

IR is not an option because these images are part of a much larger series and need to have the same look. Good idea though!

[sully75]

Can I ask...when you use filters in a LF camera, can you judge their effects by looking through the ground glass, or is it just a matter of knowing what a particular filter will do in a particular scene?

[rdenney]

Can I ask...when you use filters in a LF camera, can you judge their effects by looking through the ground glass, or is it just a matter of knowing what a particular filter will do in a particular scene?

You can see their effects by just visually looking through the filter. But you must think in terms of relative luminance of various parts of the image and not be confused by the color the filter will apply to the scene. There are some differences in spectral response between eyes and film, but you'll still get a good idea.

Rick "whose eyes aren't quite panchromatic in the way film is, but close enough" Denney

[Brian C. Miller]

can you judge their effects by looking through the ground glass, or is it just a matter of knowing what a particular filter will do in a particular scene?

Well, the filters work the same way with all cameras. You can get a sense of what they will do just by looking through them, but you need to spend some time with them and actual film (or digital).

[Jerry Bodine]

You might also use a panchromatic viewing filter, or Wratten #90 gel (if you have one) closest to your eye + various filters to help your eye to "see like film."