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  1. #21
    Sirius Glass's Avatar
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    Would an 80A filter work? I do not know its bandpass characteristics.

    Steve
    Warning!! Handling a Hasselblad can be harmful to your financial well being!

    Nothing beats a great piece of glass!

    I leave the digital work for the urologists and proctologists.

  2. #22
    2F/2F's Avatar
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    Ilford Otho is sensitive from about 350 - 550 nM to my recollection. Not sure about Rollei, or about any of the graphic arts films, such as Kodalith or Arista APHS, etc.

    Steve,

    I think an 80A boosts the right cool wavelengths in relation to the warm ones, but as it is a color conversion filter, it does not totally block the warm light as well. All it does it tweak the balance between warm and cool. I think as much as 20% of yellows through reds pass through an 80A.
    2F/2F

    "Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."

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  3. #23
    2F/2F's Avatar
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    I just found this on an astronomy Website: http://www.stellarjourney.com/images/spect2.gif

    I appears that a #47 filter will give a pan film almost exactly the same look as Ilford Ortho, not counting grain and sharpness, of course.

    Both filters seem to pass IR as well. Interesting...
    Last edited by 2F/2F; 08-12-2009 at 06:50 PM. Click to view previous post history.
    2F/2F

    "Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."

    - Rob Tyner (1944 - 1991)

  4. #24
    Sirius Glass's Avatar
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    Quote Originally Posted by 2F/2F View Post
    Ilford Otho is sensitive from about 350 - 550 nM to my recollection. Not sure about Rollei, or about any of the graphic arts films, such as Kodalith or Arista APHS, etc.

    Steve,

    I think an 80A boosts the right cool wavelengths in relation to the warm ones, but as it is a color conversion filter, it does not totally block the warm light as well. All it does it tweak the balance between warm and cool. I think as much as 20% of yellows through reds pass through an 80A.
    Thanks, I knew it was for color correction under tungston lights, so it was, if you will, a shot in the dark [pun intended].

    Steve
    Warning!! Handling a Hasselblad can be harmful to your financial well being!

    Nothing beats a great piece of glass!

    I leave the digital work for the urologists and proctologists.

  5. #25
    2F/2F's Avatar
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    Quote Originally Posted by Sirius Glass View Post
    Thanks, I knew it was for color correction under tungston lights, so it was, if you will, a shot in the dark [pun intended].

    Steve
    FWIW, it is the only blue filter I have ever used on b/w film, so I can tell you that it does indeed work. It just does not cut out warm light as severely as the 47 series. I always knew there was a better blue filter to use, but with as infrequently as I use a blue filter, I always just make do with the 80A when I need one, since it is already in the kit.
    2F/2F

    "Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."

    - Rob Tyner (1944 - 1991)

  6. #26
    gainer's Avatar
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    Quote Originally Posted by 2F/2F View Post
    I just found this on an astronomy Website: http://www.stellarjourney.com/images/spect2.gif

    I appears that a #47 filter will give a pan film almost exactly the same look as Ilford Ortho, not counting grain and sharpness, of course.

    Both filters seem to pass IR as well. Interesting...
    44A might be better.
    Gadget Gainer

  7. #27

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    My data on ortho film indicates a range of spectral sensitivity from roughly 400 to 560 nm wavelength with a peak about 540nm. The filters that seem to best approximate this are the #44 and #64, at least according to the data on the website link above.

    What is missing from the bar-graph data is the percentage of transmitted light at any given wavelength. However, the filters noted above still seem the best choice.

    Note that a blue filter like the #47, which has a cutoff above about 470-500nm, would better approximate a completely blue-sensitive emulsion. Ortho films are sensitive to the greens, which blue-sensitive emulsions are not.

    I can attest from personal experience that the #44 filter does the job of rendering an ortho-look nicely. I've never used a #64, it may be a filter for more special applications like photomicrography.

    Also, an 80B or 80A filter, even though it does not really transmit a spectrum similar to the sensitivity of ortho film, will darken reds and often gratifyingly lift shadows lit by blue skylight. This latter is one of the reasons many like the ortho look and use cyan filters. What the blue filters will not do is render green foliage much lighter than pan film, which is another of the reasons some like the ortho look.

    Hope this helps.

    Doremus Scudder
    www.DoremusScudder.com

  8. #28

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    What size do you need? I've been through my stash of Wratten 4 inch filters and found number 44, 45, 47, 47B, 49, and 61 among many others. The 49 is deeper blue than the 47's. The 61 is the darker tri-color separation filter used with a 47 blue and 29 red. I also have a 29 if anyone's interested in doing tri-color seps or multi-exposure special effects. I have numbers 25 and 58 (with the 47B) making the full set of lighter color sep filters as well.

    I haven't searched through the 2 inch filters yet.

    PM if interested any any of these or if there are others you want such as IR, ND, or CC.
    Last edited by Mike1234; 08-15-2009 at 09:24 PM. Click to view previous post history.

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