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  1. #61

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    Quote Originally Posted by jnanian View Post
    i might try my best to get over my aversion to filters .. dark blue ?

    and with the others, should it be the dark filters or the light ones ?
    I guess a "primary blue" filter (Wratten #47B) should give basically the effect of a blue-sensitive-only film. To get faux-orthochromatic, you'd need more of a "minus red", which apparently is Wratten #44A.

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    Nathan Tenny
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    -The Little Technical Library, _Developing, Printing, And Enlarging_

  2. #62

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    A colour temperature correction filter, used for tungsten light with daylight film (80A), will work too.
    It's something many people may already have.

  3. #63
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    Quote Originally Posted by Michael R 1974 View Post
    That is why I first suggested a blue filter. Jnanian said he liked the "look" of ortho emulsions.
    But you are still wrong . Blue filter on pan film naturally passes only blue, and thus "emulates" blue-only sensitive film, not an ortho film. Ortho film is sensitive to wavelengths from blue to green, so to emulate it with pan film, you need a filter that passes wavelengths from blue to green, and stops (absorbs) wavelengths from yellow to red -- that is a cyan filter.

    Blue filter would give a much more dramatic visual effect on BW image, especially with skin tones. It's definitely not "ortho" look, but more drastic. For ortho look, just go with cyan. You also lose less speed that with blue.

  4. #64

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    i realized early on into this thread that i was saying "ortho" when i meant something different ..
    i meant blue sensitive ( only!) orthochromatic ( not sensitized with dye ) film, like pre-1870s plates ... the baseline .
    at present i am shooting paper negatives, a lot of them, and i was wondering if there was a
    film equivalent to my paper negatives ... some of the papers i shoot are vc, and some are graded..
    i also do some UV exposures, ... so in the end maybe just a bluish ( i will have to experiment, dark , light, greenish/cyanish )
    and filter might works best.

    as chemical photography marches forward, it seems that we are going backwards at the same time ..
    i kind of hope that down the road there is a manufacturer of just plain old blue sensitive ortho film / plates
    instead of pan film. i know it is inferior, and difficult to harness the contrast, and "deal with" because
    of its slowness ( dyes increase the speed ) but it would be kind of nice to see a drastic change.
    instead of chemical photography trying to keep up all the BS that the digi folks want us to worry about,
    ( we've already lost color image making to the computer ) i'd like to hunker down
    and get back to the roots of photography. i know i am probably a minority,
    but images from that early time period seem to be much more interesting than
    things made in the last 100 years ...

    thanks again for all your help, suggestions and information / education ..
    john

  5. #65

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    Quote Originally Posted by jnanian View Post
    i realized early on into this thread that i was saying "ortho" when i meant something different ..
    i meant blue sensitive ( only!) orthochromatic ( not sensitized with dye ) film, like pre-1870s plates ... the baseline .

    So I think my original guess regarding the general look you were after was on the right track. I'd then say a tricolor blue (wratten 47 or 47B) would simulate the effect well as it "cuts" pretty much everything but blue. You'll get those characteristic bleak-white skies, accentuated atmospheric haze and open shadows under daylight. The 47B is darker than the 47 but might be overkill and not add much other than lengthening exposure time.

    On the other hand if you are also currently using VC paper for negatives, sensitivity is to blue and green so I guess you'd need more of a blue-green filter (wratten 44A is the only one I can think of). There is also a 44 which is similar to the 44A in the visible spectrum but is designed to also absorb UV light, so that's obviously no good if you're doing UV exposures.

  6. #66

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    I just realized I basically repeated what ntenny said. Sorry for the duplication.

  7. #67
    ath
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    Quote Originally Posted by hrst View Post
    Blue filter on pan film naturally passes only blue
    Not really. These high pass filters have a rather soft transition as opposed to low pass filters (IR, red, orange, yellow). So there is some green and even red passing though.

    See curve "Blau 38":
    Regards,
    Andreas

  8. #68

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    These are not the tricolor cutting filters though.

  9. #69
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    Quote Originally Posted by ath View Post
    Not really. These high pass filters have a rather soft transition as opposed to low pass filters (IR, red, orange, yellow). So there is some green and even red passing though.

    See curve "Blau 38":
    Well yes, the filter you show is not "blue", but more likely "light cyan-blue". It is probably meant for coloring tungsten light sources to give an impression of "blue" compared to unfiltered light. The reason why it passes so much green and even red is to increase light output level for tungsten light sources that are low in blue wavelengths. In fact, that curve is quite close to 80A color temperature conversion filter! No, it's probably more close to 80B or even 80C. There's so much red passed.

    There are also real blue filters available, and when I speak about blue filter, I really mean blue filter.
    Last edited by hrst; 02-03-2011 at 09:34 AM. Click to view previous post history.

  10. #70
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    Quote Originally Posted by hrst View Post
    Well yes, the filter you show is not "blue", but more likely "light cyan-blue". It is probably meant for coloring tungsten light sources to give an impression of "blue" compared to unfiltered light. The reason why it passes so much green and even red is to increase light output level for tungsten light sources that are low in blue wavelengths. In fact, that curve is quite close to 80A color temperature conversion filter! No, it's probably more close to 80B or even 80C. There's so much red passed.

    There are also real blue filters available, and when I speak about blue filter, I really mean blue filter.
    No, this filter is advertized as blue filter for b&w and not as correction filter. This is from Heliopan using Schott glass. Older B&W filter catalogs show similar curves for the blue filter.
    I found much narrower response for wratten gel filters but even these went up to 500nm. IDK if these are available as glass filters.
    Regards,
    Andreas



 

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