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Thread: orthochromatic film?

  1. #21

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    Re: orthochromatic film?

    Quote Originally Posted by h2oman View Post
    Pardon me if this is an ignorant question: Could a person get an effect similar to using ortho film by using a blue filter with panchromatic film?
    Quote Originally Posted by Mark Sampson View Post
    The Wratten #44 is a "minus-red" filter. When used with pan film in daylight, it will give you a tonal rendition like an ortho film. A blue filter, like a #47, will give more extreme effects.
    Quote Originally Posted by Jim Noel View Post
    ...
    2. There is NO filter which will give you the same film sensitivity and color response as orthochromatic film ,or vice versa. There are many suggestions from workers with little or no experience with ortho film.
    ...
    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
    Last edited by Doremus Scudder; 28-Apr-2021 at 15:54.

  2. #22

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    Re: orthochromatic film?

    Quote Originally Posted by Jim Noel View Post
    I have been using orthochromatic film since 1938.
    Some of my answers to various questions here are:
    1. It is naturally more contrasty than panchromatic film.
    2. There is NO filter which will give you the same film sensitivity and color response as orthochromatic film ,or vice versa. There are many suggestions from workers with little or no experience with ortho film.
    3. Ilford is probably the best ortho film available today for most people. The primary reason for this is that it is single sided and all current x-ray films that I can find are 2-sided. That is, there is an emulsion on both sides. I use probably 10 times as many sheets of x-ray as any other film because I am used to handling the delicate emulsion without scratching either side.
    4. I normally use D-23 or Pyrocat HD developers because they give me the highest speed, and are not in themselves so active as to increase contrast. The produce beautiful mid-tone contrast. Such is not true of HC110, or other "modern" developers.
    5. I grew up developing by inspection, and continue to prefer that method, although I no longer attempt to teach it because most people today are unable to learn to see the correct contrast. It takes lots of time and lots of practice. My estimate is development 100-150 sheets of ortho is necessary to get efficient.
    6. There is no better emulsion for portraits of older men, images made in Utah of red cliffs, Autumn leaves, etc.
    I could go on, but that is enough. I do not and will not argue with newcomers, those with under 75 years experience. BUT - if you consider what I have said, your appreciation of ortho film will improve.
    Quote Originally Posted by Jim Fitzgerald View Post
    I would go with what Jim said, after all 83 years of experience kind of counts a lot in my book.
    Yes, I was thinking of made a test on D23. Thank you
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  3. #23
    Drew Wiley
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    Re: orthochromatic film?

    It all depends on what you're priority is - development by inspection, or a certain kind of look in the scene? You need real ortho film for the former, but can skin the cat any number of ways in the latter instance. But why not experiment with real ortho while it happens to be around? It's not going to blow up like a 1950's chemistry set.

  4. #24
    Nodda Duma's Avatar
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    Re: orthochromatic film?

    Doremus, I think what you’re missing, and perhaps what Jim has in mind, is that the response of classic Orthochromatic film continues down in to the ultraviolet. Modern panchromatic film has been designed to block ultraviolet to stabilize the speed of the film throughout a year’s variation in UV. A red filter will cut out the red, yes, but will not add the ultraviolet sensitivity of a classic ortho emulsion to a panchromatic film. Hence an insurmountable difference.
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  5. #25
    Drew Wiley
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    Re: orthochromatic film?

    In the case of the current Ilford Ortho product, the sensitivity falls off rather quickly below 400nm, so I wouldn't personally consider it particularly UV responsive, just marginally so. And the light-scattering tendency of UV with respect to atmospheric haze would seem to lead to less sharp images in certain instances. But I suppose it depends on just how UV much gets through the lens elements to begin with.

    I'd be curious just how far Fuji Acros can be tweaked into a general Ortho look, sensitometrically. It's orthopan, and already in effect more green responsive than pan films, due to being distinctly less red sensitive. And its sensitivity extends into the UV range. From a practical standpoint, it seems pretty easy to leverage the Ortho direction with very modest filtration tweaks. I have a lot of experience with it. But in sheet film version, sadly it is no more; so this becomes a hypothetical.

  6. #26

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    Re: orthochromatic film?

    It's funny how threads often outlast the attention span of the OP, but I'm still following!

    Maybe I should be more specific about what I'm looking for. I'd like to get sort of a Watkins/O'Sullivan look when photographing high desert landscapes in mid-dayish light under clear skies. If I can get there using a filter with panchromatic film, that would be great - the simpler the better. I'll probably start by trying a filter and see if I can get the effect I'd like.

  7. #27

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    Re: orthochromatic film?

    Quote Originally Posted by h2oman View Post
    It's funny how threads often outlast the attention span of the OP, but I'm still following!

    Maybe I should be more specific about what I'm looking for. I'd like to get sort of a Watkins/O'Sullivan look when photographing high desert landscapes in mid-dayish light under clear skies. If I can get there using a filter with panchromatic film, that would be great - the simpler the better. I'll probably start by trying a filter and see if I can get the effect I'd like.
    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.

  8. #28
    Drew Wiley
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    Re: orthochromatic film?

    I already gave the clue : a medium light blue filter like an ordinary 82A or 82B will get you somewhat there, without going overboard or drastically lengthening exposure times. But a 47 deep blue will give more of the authentic blue-sensitive-only look of antique films; even greens will go very dark, and blue skies will end up essentially white. The even stronger 47B filter is essentially overkill, and will require even longer exposures. A filter factor of 6X or three stops of compensation is required for a 47 filter when using most pan films; 8X or four stops is characteristic of 47B. Sometimes all that extra exposure time is an advantage, like when using the lenscap exposure method with barrel lenses.

    And yes, I've achieved the feel of mid-day glare and sheer overwhelming light in the desert in this manner. And if blacks can be blocked out for optional graphic effect, so can whites, as a kind of reverse silhouette, something O'Sullivan was a master at.

  9. #29

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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.
    +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

  10. #30
    Drew Wiley
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    Re: orthochromatic film?

    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.

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