T-Max Film and Using Yellow Filters?

Discussion in 'Black and White' started by Vincent Peri, Feb 14, 2021.

  1. Vincent Peri

    Vincent Peri Metairie, LA

    I read somewhere (maybe here) that T-Max 100 and 400 film don't need a medium yellow filter in order to get a proper contrasty sky. Has anyone noticed this, or is a yellow filter required for the sky to not be washed out.

    Thanks for any info.
     
    Last edited: Feb 14, 2021
  2. Early black & white films were only sensitive to blue light. As such blue objects recorded too dark on the film, thus too light on the print paper. Further, red cheeks and lips reproduce, on the print too dark, may be black. Blue sky appeared too light on the print thus white clouds will not stand out against a blue sky.

    (All changed when Vogel, Professor of Photography at Berlin Technical. Trying to solve a problem called an halation, he dyed film emulsions yellow. This trick worked plus the dye somehow forced the film emulsion to become sensitive to green light. This film, called orthochromatic, greatly improved the ability of films to realistically image-colored objects.

    Vogel, and his graduate students experimented with other dyes and films sensitive to red, green, and blue, called panchromatic, resulted.

    Still, blue sky reproduces as light gray. Clouds illumined by sunlight also reproduce light gray. Mounting a yellow filter, blocks some of the blue light of the sky. Thus blue sky reproduces darker. When so imaged, white clouds are caused to stand-out (added contrast) as they reproduce light gray against a darker gray sky.
     
    Last edited by a moderator: Feb 16, 2021
  3. eugen_mezei likes this.
  4. Different films go to different wavelengths in the red.

    I don't know that T-Max films are much different from most others.
    There are a few known for extended red sensitivity that lightens some skin markings.

    Also, the data sheet for each film will give the filter factors that apply for that film,
    most specific than generally for that color filter.
     
  5. I don't see anything in the published spectral response curves to support that.

    T-Max films aren't that much different from any other film on the market in spectral sensitivity.
    IR and non-panchro films excepted of course.

    Nearly all are nominally flat from 350 to 600nm, with none having a red sensitivity much beyond 650nm.

    The use of coloured contrast filters, and polarisers, was recently covered in another post.

    My own conclusion is that an orange filter or polariser is needed to make a significant difference to the rendering of a blue sky.

    FWIW, here are the spectral response curves of some films:

    Agfa -
    Agfa-spectral-all.jpg

    Fuji Neopan -
    Fuji-spectral.jpg
    Tri-X - Tri-X_spectral.jpg T-Max 100 - T-Max-100_spectral.jpg Tri-X_spectral.jpg T-Max 400 -
    T-Max-400_spectral.jpg
    All looking pretty similar so far.

    And then Ilford FP4plus -
    Ilford-FP4plus-spectral.jpg
    Like all of Ilford's data, it's useless; badly scaled and, in this case, exposed to Tungsten lighting that skews the spectrum.
    Pull your finger out Harman!
     
    Last edited: Feb 15, 2021

  6. Hi Alan,

    If I remember correctly (and I may be mistaken about the film type), back in the 1950's when I first learned to develop film, we developed orthochromatic film by inspection under a dim red safe light. If the dye forced orthochromatic film to become sensitive to red light, this would not have worked. What type of film was I developing?
     
  7. TP2415 says that it had "extended red sensitivity" to 690nm, which makes a difference on skin tones.

    While it is common to consider the visible spectrum between 400nm and 700nm, the long wavelength
    part has a long tail, not a sharp cut-off.
     
  8. Vincent Peri

    Vincent Peri Metairie, LA

    Thanks for all the comments. I'll be using a medium yellow filter once I start shooting my T-Max film.
     
  9. Most likely - Kodak Verichrome or equivalent. Natural silver emulsions are only sensitive to violet and blue. Sensitizing dye is routinely added to force the emulsion to gain sensitivity to the longer wave lengths such as red and green.
     
  10. I think Verichrome was the last of Kodak's consumer grade orthochromatic films. I found an old Kodak ad in a 50's photo magazine that promoted Verichrome (with a yellow filter) as a thrifty medium for photography. Not sure if Ansco or Ilford were still offering orthochromatic films at that time.
    Writers of screenplays and TV shows seemed to think darkrooms had to have red lights so even in the days that panchromatic films were mostly all that was available the TV/movie darkroom was lighted in red.
    Only one I remember was when the local newspaper was still shooting large negatives of pages to be printed they used red safelights at the film was orthochromatic.
     
  11. Dye extended sensitivity into the longer wavelengths.
     
    Last edited by a moderator: Feb 16, 2021
  12. A complicating factor is that the blueness of the sky varies greatly.
    Near the horizon it is very pale and a yellow filter will have little effect.
    The sky is deepest blue on a clear day at noon on the side opposite the sun and about half way up to the zenith. Here a yellow filter will darken the sky strongly and if photographing at altitude the sky can come out almost black.
    [​IMG]
    This is an shot on Tmax 400 8x10 format with a yellow filter. The sky came out too dark and suffered a tonal merger with the tree leaves.
     
  13. Do yellow, orange and red filters show their effect on digital camera screens set for BW?
     
  14. The switch from V to VP is about 1956.

    Many panchromatic films are older than that.

    My though, which I don't have any reference for, is that it stays longer so that home processing with a red light would be easier.

    When I first got into darkroom photography, when I was nine, my dad bought me a contact printer from Goodwill, which included a Brownie red safelight. At that time, if you bought a Brownie safelight it came with yellow and green filters. I had that red safelight for printing for many years. (I think I still have it.)

    But before the contact printer, I already had a Yankee II tank. Tank development seems so easy.

    But yes, it does seem that Verichrome (not Pan) stayed around longer than it should have.
     
  15. Of course they do.
    Why wouldn't they?
    The switch to time-and-temperature development, in light-tight tanks, was generally far earlier than 1956.

    Only a few die-hards were still developing in trays by inspection in those days.... except in the reprographics trade where red-yellow insensitive lith materials were used.
     
  16. Well, the digital camera is switching color to BW after the sensor. I'm thinking that BW film handles it differently so the final result between the two does not match in intensity or other factors? The point I'm making is that if I compare a digital camera's response comparing red, orange and yellow filters, will the digital results tell me which filter to use with the film?
     
  17. With a little practice you should be able to look through the filter at the subject and decide if you need it. I had always heard that ordinary panchromatic film would give a more accurate tonal rendering with a yellow filter. It certainly helps blue skies, but I often prefer something a bit stronger- yellow does come in several densities, K1, K2 and K3. See https://www.freestylephoto.biz/static/pdf/pages/bw-filters_01-28-2014.pdf
     
    bgelfand likes this.
  18. That is what I would have thought, but I suspect that they were allowing for the small number of first-timers, maybe who couldn't afford a tank.
    To make it as easy as possible for beginners.

    There was Plus-X from about 1938 if you wanted a panchromatic film, and Super-XX for a faster film.
    I believe that those came in some sizes, such as 620, that would be later discontinued.
     
  19. The filters will give different results with different films, and also with different digital cameras.
    With the digital camera, you also have to select the weights for the RGB conversion.
    Much of the time, you don't need a filter, just change the RGB weights.
    Also, in the case of film, you can use color film and convert to black and white later,
    and use any filtering (optical or electronic) when you do that.
    I still have some Panalure, black and white paper for printing color negatives.
    I even have a #13 safelight to go with it.
     

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