Controlling exposure using filter...

[dan nguyen]

There are techniques of controlling exposure such as Zone System and development, neutral filters etc etc...Let's say that I have to take a photo using B & W film and I have no choice to wait for better light and there is an area in the scene that has blown-out high lights which I can see it on the ground glass. I wonder if there is a technique using a filter such as UV or Skylight and smear on the part of the filter that corespond to the blown out on the scene using a subtance similar to pencil lead or something else... The idea is block out part of the scene which reqquires less alteration in the film development process. Anybodyknow about this technique (if it exists) and what subtance was used for it...? I search around the Net can't find the answer....
thanks...

[Donald Qualls]

Anything as close to the lens as a filter will be grossly out of focus; you'll have a "burned" area with a very fuzzy border; that way lies a halo of the sort caused by heavy-handed dodging or burning in printing. Worse, you'll be recording forever your ability (or inability) to match the shape of a blot on a filter to the shape of a troublesome highlight.

If the highlight area is small, I'm often inclined to simply let it block, but I also often find that modern film has faithfully recorded detail in the highlight -- detail I can't scan (without sacrificing the darks or making the whole image look flat and gray) and will find it difficult to print (as above, and because I'm not really up to speed on burning in, yet), but detail that's on the negative anyway.

The classic Zone approach is to expose even more, and then give N- development to tame the problem highlight (maybe N-2 or N-3, if you have a film that will do that -- few modern films will), and split print to bring back the overall contrast, while burning the troublesome highlight with the soft filter. Another approach that might work in some cases is to use a filter that preferentially darkens the color of the highlight without pulling down the shadows as much (in sunlight, a blue or cyan filter would be the right choice for this). I'd be inclined to think even local bleaching of (a copy of) the negative would be preferable over a spot-density filter of the sort you describe.

[jantman]

If you're a traditionalist, you use the Zone system, and a film like Bergger BPF-200 which allows for dramatic expansion/contraction. If you're into the whole digital thing, make a number of braketed exposures and then Photoshop yourself a final image.

However, remember this: Photography is not Magic.

As much as we like to say that we can make the camera do what we want, that we can shape and influence our images, they are still a record of something the camera saw, and as such are constrained to the limits of the technology.

Film, and for that matter digital, can only image a certain range of luminance values. At some point, the highlights will block, and the shadows will lose detail. It's simply a fact of the process. So, you use techniques like the Zone system, and figure out a compromise.

[james mickelson]

Yes you can provided you can match the bright area to some degree. Skies are the easiest to do. I use my darkslide and make the exposure time a little longer so I can make the dodge in camera. I use my darkslide and wave it about an inch or so in front of the lens to approximate the area needing to be dodged. You look at the groundglass, then you figure out where you need to dodge with the corner or edge of your darkslide. Remember that the image is inverted on the groundglass and you have to dodge the opposite side of the lens. This is not a big deal. I've seen Sexton and Barnbaum do it and I've done it numerous times with very good results. It takes practice but it is a very useful tool if you master it and shoot a lot outdoors in uneven lighting conditions. If you wanted to get really exact you could take a clear filter like a skylight or UV and carefully smudge the area corresponding to the area on the image that needs to be dodged. I did it a lot at Mono Lake once when the sky was very very bright and the foreground very dark. All I wanted was the fine detail in the sky and some foreground detail but not much. The film I had didn't take expansion and contraction at all so I fooled around with this idea and it worked. The object you use is so close to the lens that it virtually disappears. Be careful though with flare along the edge of the object you might use to dodge. But give it a try. Hurrell used it in the studios a lot. That's also what barndoors are for when needed. Different technique though. Have fun. Film and processing are cheaper than having to go back to a spot and shoot again.

[John_4185]

In addition to the good suggestions so far, I see two omissions.

If the brilliant highlight is reflected polarized light - try a polarizer. It might bring the highlight down to a reasonable level.

I know some people might rail against the next suggestion - Tiffen ultracontrast filters. These are colorless filters that diffuse light into the shadows and can lower overall contrast remarkably without severely degrading performance. You have to try them to believe, or not. Tiffin's page doesn't do them justice, but check them out at www.tiffen.com/contrast_filters.htm

[Brian C. Miller]

Pyro.

[Richard Schlesinger]

How about making a mask?

[dan nguyen]

Thank you all...

As LF format users I think we are all a bit of tinkerers and experimenters... I asked the question out of a moment of frustration in the darkroom...

James, since I already familiar with other's suggestions, your's is as same as my crazy idea... so... what did you use to smudge the filter...?

thanks again...

[David A. Goldfarb]

For compositions that lend themselves to it, you can use ND grad filters in B&W just like they do in color. Even better than color, you can use color grads in B&W without the cheesy results. Try a tobacco grad with a B&W landscape, and you can both darken and increase the contrast in the sky without changing the values in the foreground.

[james mickelson]

I used a sharpie which I always carry in my bag. It wipes off glass surfaces easily. You can apply it when it is on the lens and see the results on the GG. But if the bright area is in the horizon area then I would wave a darkslide or if in the field I would find a leaf and use it as a dodging tool just as you would in the darkroom. Your GG is your canvas and you can guesstimate where you need to dodge by looking at the GG. As long as the tool is close to the GG (1 inch) you won't see the tool of the negative. Remember to lengthen considerably your exposure by stopping down. Tough on windy days I know. Out here in the west and southwest, there is such a large spread between light and dark areas especially in the evening when shooting against the sky. Try it. Film is cheap. It also works on color film. Black that is. Film will pick up the color of the item. Not much but enough.