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Thread: orthochromatic film?

  1. #31

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    Re: orthochromatic film?

    Not remotely my area of expertise, but there was a discussion on Photrio where a cinematographer was trying to get an "ortho look" out of Kodak Double X film. He ended up using a short pass filter--SP570, IIRC. If you want to see the results the film came out a couple of years ago called "The Lighthouse".

  2. #32

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    Re: orthochromatic film?

    Quote Originally Posted by Doremus Scudder View Post
    +1

    You'll be needing to approximate a blue-sensitive emulsion. Try a Wratten #47 to start. You may have to use a gel filter; glass may be harder to find. Possibly Tiffen still offers them in glass.

    I'm not sure where you can get the dichroic filters maltfalc is referring to. Maybe "dichroic" in this sense refers to blocking two of the primary colors, passing only one (blue in this case). Maltfalc, can you elaborate?

    But, the one need not exclude the other. Take out your trusty camera and filters and make shots with a #47, a #44, an 80A and whatever else you want to experiment with and see what gives you the results you want.

    @Nodda Duma

    Yeah, I'm aware that using filters on panchromatic film is just an approximation. Still, I've had results I like using filters, even though they may be (markedly) different than real ortho film. Still, I wonder how much UV gets through modern lenses anyway...

    I have been getting more interested in the ortho rendering of tones lately; maybe I'll have to order some Ilford Ortho and do some work with it.

    Best,

    Doremus
    Quote Originally Posted by Drew Wiley View Post
    I think dichroic is a totally wrong designation in this case. Glass filters of this type are either tinted glass, with or without supplemental coatings relative to reflection control, or sandwich-style, with the filter material between sheets of glass, the Tiffen method. 47's are still easy to get, although I strangely notice that the current Tiffen version is weaker than the older ones. I still have the older 47B's too, so haven't searched for any of those lately. I sometimes use the denser 47B version for actual color separation work; but viewing through the groundglass to evaluate the effect is difficult with a filter that dense, so the slight weaker, but one full stop brighter, 47 makes more sense in the field for black and white shooting applications.
    dichroic filters are essentially mirrors that are transparent to some colours but reflect others with nearly 100% efficiency, which is why they're used in colour enlargers, dlp projection tvs, rgb lasers, three-ccd video cameras, hot mirrors for digital cameras, etc.. you can get them at b&h and a bunch of other places. a short pass dichroic filter reflects all light above a certain wavelength, so a blue short pass dichroic filter will cleanly chop off anything pre-ortho film or plates weren't sensitive to while giving you near 100% transmission of blue, violet and whatever uv can penetrate the glass. standard filters won't let through nearly as much of the light you want or block all of the light you don't want.

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  3. #33
    Tin Can's Avatar
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    Re: orthochromatic film?

    Gonna watch that again

    Quote Originally Posted by abruzzi View Post
    Not remotely my area of expertise, but there was a discussion on Photrio where a cinematographer was trying to get an "ortho look" out of Kodak Double X film. He ended up using a short pass filter--SP570, IIRC. If you want to see the results the film came out a couple of years ago called "The Lighthouse".
    Images vastly preferred

    not game trying to


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    In Time

  4. #34
    Nodda Duma's Avatar
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    Re: orthochromatic film?

    Quote Originally Posted by maltfalc View Post
    if you want "a Watkins/O'Sullivan look" then you don't want an ortho look, you want the look of plates that were mostly sensitive to blue and violet. with pan film a blue dichroic short pass filter is your best bet.
    Of course, if you want the look of plates, then you can just shoot plates.
    Newly made large format dry plates available! Look:
    https://www.pictoriographica.com

  5. #35

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    Re: orthochromatic film?

    You blew my mind a little, Doremus. I either forgot, or never knew specifically what movie Jarin was preparing for, and when I saw The Lighthouse I didnít pay enough attention during the credits (actually I was pretty disappointed with the movie) so I never made this connection. I remember exchanging a lot of PMs with him at that time because I think he was trying to figure something out with pyro.

    Wow.

    Quote Originally Posted by Doremus Scudder View Post
    Let's be a bit more specific here.

    Ortho film almost certainly has different characteristics than filtered panchromatic film, which make it unique. (I'm sure different ortho films have characteristics slightly different from one another too; it's just that these days, the choices are rather limited...)

    That said, one can approximate the spectral sensitivity of orthochromatic film by using red-blocking filters with pan film. The end result, i.e., the exact spectral sensitivity, of the filtered pan film will, of course, depend on the exact filter used and the spectral sensitivity of the film used. Still, the effects obtained by using red-blocking filters on pan film can be gratifying and one doesn't have to carry extra film, just some filters.

    And, let's differentiate between older blue-sensitive emulsions and orthochromatic emulsions. The former are the "original" photographic materials, the silver halides alone, which are only sensitive to blue light, not green or red. Later, emulsion formulators learned to add sensitizing dyes to the emulsion to make it sensitive to green as well as blue. These blue-green sensitive emulsions were named orthochromatic. Even later, when components were found to make film sensitive to blue, green and red, thus better approximating the visual spectrum, panchromatic emulsions became common.

    So, filtering the red out of the light reaching a panchromatic emulsion gives a similar spectral response as orthochromatic film (Jim, note I'm saying "similar," not exact ). The classic minus red filters are the Wratten #44 and #44A, which were originally used in color separation work. Ansel Adams recommended those filters for approximating the effects of ortho film with panchromatic emulsions. Optical-quality cyan filters will block red and can be used for the same purpose as well. The effects will vary depending on exact spectral characteristics of the filter and film. And, I've had pretty good luck getting an ortho effect on pan film using the 80A and 80B color-conversion filters. They look blue, but pass quite a bit of green and a bit of red (they were originally intended to convert tungsten light into something better approximating daylight when using daylight-balanced films, especially transparency materials, with tungsten lighting, which is much redder).

    Using a Wratten #47 filter or similar, that passes only blue light, will give an effect more similar to the old blue-sensitive emulsions, as they don't pass any green light. They are also a useful tool, but will not, strictly-speaking, give the "orthochromatic effect" that other filters that pass green as well as blue do.

    An interesting read on the specific application of using filters to obtain an "ortho look" would be to find the thread over at Photrio started by Jarin Blaschke here: He was the cinematographer for the award-winning film "The Lighthouse" and had filters specially made for his cine film (Plus X?). He eventually had filters specially made to suit his needs.

    Best,

    Doremus

  6. #36

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    Re: orthochromatic film?

    Quote Originally Posted by Nodda Duma View Post
    Of course, if you want the look of plates, then you can just shoot plates.
    well yeah. i was just answering his question specifically about filtering pan film. blue sensitive x-ray film would also be a dirt cheap and easy option that can be developed under most safelights.

  7. #37
    Drew Wiley
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    Re: orthochromatic film?

    maltfalc - I'm very familiar with dichroic coatings. The biggest manufacturer of these in the world was once nearby, and their former catalog would stun you. No, you don't get them at places like B&H, unless its just a mild or "colorless" UV filter (I'm wearing coated "computer glasses" right now). Nor are these kinds of coatings used for ordinary taking contrast filters. Vacuum deposition techniques apply to both categories, but for different reasons. With camera filters, it's mainly to fine-tune only tiny transmission characteristics and control reflections, just like multicoatings on modern lenses. The kind used in enlarger colorheads are incidence-angle specific in terms of transmission/reflection characteristics, so would not be dependable in an ordinary photographic application where a lens accepts light from a range of angles. I built what is probably the only privately-owned true simultaneous additive halogen enlarger in the world using dichroic "sandwich" trimmer filters, which cut off the bandwidth on both sides of the desired RGB peaks. But I'm no optical engineer. I merely consulted with them.

    There is a real engineer responding to this thread, if he wishes to describe the distinctions more precisely than I can, or correct me as per my own definition of "dichroic". But as I already noted, contrast filters for black and white photography, which are the kernel of this aspect of the discussion, are primarily made of either dyed-in-mass glass, or via the colored thermo-foil sandwich method that Tiffen uses. Any optical coatings are secondary. As far as laser applications go, I once sold certain industrial lasers, which doesn't make me an expert in that field either, but knowledgable enough to understand a number of basis issues.
    Last edited by Drew Wiley; 29-Apr-2021 at 19:52.

  8. #38

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    Re: orthochromatic film?

    About a year or so ago i picked up some Ortho film from Photowarehouse on a whim and it was pretty dang cheap. Just an FYI. Still haven't used any of it yet.

    I just checked and they still have it. 100 sheets of 4x5 is only $29.

  9. #39

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    Re: orthochromatic film?

    Quote Originally Posted by Nodda Duma View Post
    Of course, if you want the look of plates, then you can just shoot plates.
    I was just waiting for someone to suggest this!

  10. #40
    Drew Wiley
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    Re: orthochromatic film?

    I dropped enough plates already this week. (One is too many, especially in the kitchen.)

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