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  1. #91

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    As to orthochromatic film, I am curious not so much about the colors filtered in or out, but rather about the contrast produced. Is it true that orthochromatic films are higher in contrast than panchromatic films?

  2. #92
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    Personally I like the way orthochromatic film picks up the skin details (o blemishes, depending on the model).
    It's probably not the most flattering film out there to use for portraits, but I like the sense of texture that it gives to the skin and I think it works very well with the right subjects.

    I only tried Ilford Ortho Plus, so I'm not sure how the other films vary.
    I bought it because I was curious to try something different and I wanted to recreate a certain effect that you get when using emulsions with reduced sensitivity to certain bandwidths.


    Regarding contrast, I used a low contrast developer and very soft light, maybe next time I should try to see how contrasty it is with a normal developer.
    Any recommendations?

    Another question for the experts: if the results of using ortho film are exactly the same as using pan film with the right filter, why is ortho film still sold? isn't there anything that distinguish ortho from pan other than the sensitivity to red?

  3. #93
    AgX
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    Quote Originally Posted by Gerald C Koch View Post
    To make everything clear.

    orthochromatic film sensitivity 375 to 560 nm
    isochromatic film range extended to 620 - 650 nm
    panchromatic film range extended to 660 - 730 nm
    -) there is no general definition of those terms, let alone with that precision.

    -) the spectral sensitivity spread within the ranges varies substantially between films. Also the typical curves changed over time.

    -) a film designated as panchromatic b&w typically reaches as far as 660nm

  4. #94

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    Quote Originally Posted by Gerald C Koch View Post
    To make everything clear.

    orthochromatic film sensitivity 375 to 560 nm
    isochromatic film range extended to 620 - 650 nm
    panchromatic film range extended to 660 - 730 nm

    Sorry to be negative about ortho films but I have been going thru some of my older photos and find that they are not as good as they could have been if a better panchromatic film had been used. Of course my choices were limited at the time. On doing further research and looking at the films I used my comment about "featureless skies" may have been caused by the sensitivity of early panchromatic films. Early panchromatic films were overly sensitive to blue light and therefor did not represent colors in the correct shades of gray.
    gerald:

    you mean, you didn't combination print them with a cloud screen?

    john

  5. #95
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    I enjoyed using Kodak Copy film http://www.kodak.com/global/en/profe...bs/f17/f17.pdf

    From the above link:

    "With most black-and-white films, the contrast of
    negatives is controlled by development. However, with
    KODAK Professional Copy Film, contrast in the copy
    negative is controlled by both exposure and development.

    Development controls the contrast of the midtone and
    shadow regions of the negative (and to a slight extent, the
    highlight region), while exposure primarily controls the
    contrast of the highlight. For a given development condition,
    as the exposure increases, highlight density increases at a
    faster rate than shadow density, increasing the overall
    contrast."

    I do not know if it had to do with it being a ortho film, but it was very useful in getting greatly increased highlight contrast, or density in the highlights, for making carbon prints. One had to be careful using it -- a little more exposure and a little more development and the highlights would take off like a herd of wild horses. But it was great for expanding a normal contrast scene, yet keeping a nice even tonality.

    I have a Kodak Copy Film negative that one needs a very bright light behind to see anything in the highlights...they looked blocked-up. But the resulting carbon print kept wonderful detail and separation of the tones in the highlights (sun-lite granite).

    I tried some of the Rollei Ortho 25...not the same stuff as the Kodak Copy and I did not have enough of it to tame the horses properly.
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

  6. #96

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    Quote Originally Posted by Gerald C Koch View Post
    To make everything clear.

    orthochromatic film sensitivity 375 to 560 nm
    isochromatic film range extended to 620 - 650 nm
    panchromatic film range extended to 660 - 730 nm
    Source? I tried yesterday (in a fairly shallow way) to find a standard definition for the terms and came up empty.

    (If you take Rollei at their word that the sensitivity stops at 610 nm, by these definitions that would make it "not quite isochromatic". I suppose you can insist on rigorously distinguishing it from "true ortho" on that basis, but I'm not sure why it's important.)

    -NT
    Nathan Tenny
    San Diego, CA, USA

    The lady of the house has to be a pretty swell sort of person to put up with the annoyance of a photographer.
    -The Little Technical Library, _Developing, Printing, And Enlarging_

  7. #97

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    Quote Originally Posted by ntenny View Post
    Source? I tried yesterday (in a fairly shallow way) to find a standard definition for the terms and came up empty.

    -NT
    From the following site.

    http://dacnard.wordpress.com/2013/02...of-heart-pt-1/
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  8. #98

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    Quote Originally Posted by Gerald C Koch View Post
    ...whose apparent source is an article by Torsten Andreas Hoffmann, and I don't know what Hoffmann's source for the numbers was---but even that says "approximately 560-600 nm" for the ortho ceiling.

    We're totally splitting hairs here, I know, but I think it's kind of unreasonable to pick a lower bound from a source of nonobvious provenance, drop the word "approximately", and say "the hard limit is X, full stop"!

    -NT
    Nathan Tenny
    San Diego, CA, USA

    The lady of the house has to be a pretty swell sort of person to put up with the annoyance of a photographer.
    -The Little Technical Library, _Developing, Printing, And Enlarging_

  9. #99

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    Quote Originally Posted by ntenny View Post
    ...whose apparent source is an article by Torsten Andreas Hoffmann, and I don't know what Hoffmann's source for the numbers was---but even that says "approximately 560-600 nm" for the ortho ceiling.

    We're totally splitting hairs here, I know, but I think it's kind of unreasonable to pick a lower bound from a source of nonobvious provenance, drop the word "approximately", and say "the hard limit is X, full stop"!

    -NT
    When you specify a range of values that is the equivalent of saying approximately. I too am tired of splitting hairs. I posted a personal opinion which has taken on another aspect.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  10. #100
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    Quote Originally Posted by lensmagic View Post
    As to orthochromatic film, I am curious not so much about the colors filtered in or out, but rather about the contrast produced. Is it true that orthochromatic films are higher in contrast than panchromatic films?
    NO!

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