47 and Long exposures

Discussion in 'Exposure Discussion' started by kintatsu, Feb 26, 2013.

  1. kintatsu

    kintatsu Member

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    Reading over the transmission specs of the 47 and 47b filters got me thinking about using them to decrease the high contrasts in night time city shooting.

    Does anyone have any experience in using a blue filter to tone down the harsh lights in the city during 30+ second exposures?

    Given that the lights often meter at 1/30 at ISO 125 in a typical city scene, and the shadows may require exposures into the reciprocity effect regions, using a blue filter when sodium, halogen, or tungsten lights are present seems to me a viable workaround. I'm pretty sure that this may be more appreciable during the early evening, blue hour, times.
     
  2. Mike Wilde

    Mike Wilde Member

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    I have not tried this personally, but your theory makes sense to me a s a colour ra-4 printer. Too Yellow scene/light source; dial in minus yellow, which we usually call blue.

    The challenge is, at night the highlights, being artificial discharge light sources are many many stops brighter than so much of the other areas we are imaging.
     
  3. michael_r

    michael_r Subscriber

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    It really depends on what type of photography you're doing - ie what kinds of light are present. I do mostly urban landscapes at night. Way back I tried some experiments with some purple/violet filters in night scenes that included sodium-type lights. This was before I really understood light and filtration. The flaw in my reasoning was that while the filters would attenuate the light sources somewhat, I failed to account for the fact everything else in the scene was illuminated by those wavelengths, so all I ended up with was an underexposed scene.

    I eventually learnt to control extreme contrast with negative exposure/development and mostly with printing techniques.
     
  4. David Allen

    David Allen Member

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    Have you considered using a two-bath developer? This is what I use and all you need to do is expose for the important shadow areas. The developer stops the highlights burning out even if shooting towards a light source.

    You can see three examples from an exhibition I had featuring my night photography:

    http://www.fenster61.de/portfolio/ds-allen-night-shift

    Best,

    David
    www.dsallen.de
     
  5. polyglot

    polyglot Member

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    So you're trying to reduce contrast by dialing back the light sources? If your scene is lit by the same lights, then it too will get darker and you will go nowhere except to stupidly long exposures - it'll just be like using a powerful ND.

    A blue filter would be useful though if you wanted to cut out sodium streetlight and then manually light your scene with blue or white light.
     
  6. kintatsu

    kintatsu Member

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    Actually, I failed to make my intentions clear.

    What I'm referring to is shooting middle to late evening, during the blue hour. There's a decent amount of blue ambient light in our area, with open spots lit by the sky. Indeed, the ambient puts a blue cast on these areas. The sodium lamps, being yellow and of higher intensity than the ambient, create distractions and burnt out spots.

    By giving proper exposure for the shadows, with a blue filter, a more balanced image can be created, at least in theory, without resorting to severely decreased development or other controls. I've found that just decreasing development requires higher grades of paper, as it often flattens the negative.

    I'm hoping to get more images during these hours, and getting them as close as possible to what I "see in my mind" in camera.

    I was just wondering if anyone had tried something similar.
     
  7. polyglot

    polyglot Member

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    Fair enough then. I'd have thought it'd be easier to just shoot earlier (half an hour?) when the ratio is more like what you want. I guess that doesn't work if your streetlights come on late or something.

    The other neat option if you have the chance to stay still for a single shot is to multiple expose - one before sundown with daylight, one later with just the streetlights. You can balance them any way you like then.
     
  8. kintatsu

    kintatsu Member

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    Thank you to everyone for the replies.

    I hadn't thought of double exposing the shots. I plan to make some shots when time allows in Regensburg, so I'll give it a try. The downside to this is getting the time between shots. I'll probably try with the 47, too.

    As for 2 bath development, I have no experience to comment on this, but my workspace is limited and getting the stuff may prove difficult. Where I'm at I have to order my chemicals from the local dealer and wait, sometimes weeks, for them to come in. I have considered trying divided D-76, but with my tight space and availability it may not be feasible.

    Thanks, all!