Same C41 film with different orange hued negatives

Discussion in 'Film and Processing' started by keithhayes, Jan 2, 2022.

  1. I noticed that the orange background color is different from each other. Both are shot on Ektar100 but were cut from different rolls. I looked at Ektar100 negatives from past shoots. They resemble or look exactly like the negative on the left. Would anyone happen to know what possibly could have made this color shift to the neg on the right?

    Thanks.

    Ektar100.jpg
     
    Last edited: Jan 2, 2022
  2. I've seen this, but rarely on contemporary film. Over time, though, the manufacturers have regularly shifted the shades of the mask on the negatives as chemicals and substrate evolve.

    Settings on scanners/apparatus also can produce different shades on even the same roll and even the same image:

    Ilford XP2 chromogenic film on a Nikon 9000 scanner will occasionally override the B&W controls and "run home to mama" with color.
    [​IMG]
    [​IMG]
     
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  3. oops? Don't know what happened , but in case anyone cares:
    Exa-1c-17-bw.jpg Exa-1c-17.jpg

    two subsequent scans on Nikon 9000 with same settings. Go figure.
     
  4. As you know, black & white film photography generates an image by chemically depositing a layer of metallic silver on film. This silver laydown is in proportion to scene brightness. The film thus displays varying translucency that controls how much light traverses the film at any given location.

    Color photography is a subset of this technology. The colors are obtained by replacing the silver with dye. Basically, three emulsions are layered, one sensitive to red, one to green, and one to blue light. These are black & white emulsion. They develop up as three separate silver images.

    A search was on, following World War II, to make sensible color films that are easy to process. The goal was a film that reproduces a faithful image.

    The answer, put colorless dye in each of the three emulsion layers. To get a colorless dye, it must be incomplete, and all three should be missing the same ingredient. If they gain this missing component, they blossom forming brilliant cyan, magenta, and yellow dyes. Such a strategy will greatly reduce the pool of suitable dyes.

    The Kodak E-6 (color slide film) and Kodak C-41 (color negative film) use the missing ingredient idea. They are called incorporated color film because the dyes are placed in the film at the factory. The developer is a black & white formula plus the missing ingredient.

    Basically, the film is placed in the developer. A three superimposed black & white silver image results. As the silver image evolves, the silver takes on oxygen that is dissolved in the waters of the developer. This silver oxide acts as a catalyst causing the missing ingredient to unite with the three dyes. A cyan dye image is thus overlaid atop the silver image in the red emulsion. A magenta dye image in the green emulsion. A yellow image in the blue emulsion.

    Now all three needed dyes are in place, however the image is veiled by the silver images. A bleach bath followed by a fix bath removes the silver images. The film emerges, the dyes have blossomed making a color film image.

    The image is not faithful. The need to find three dyes missing the same ingredient is responsible. A yellow dye should pass red and green light with little interference, and it should block blue light. This is what happens, the yellow dye is acceptable. The magenta dye should allow blue and red light to pass without restriction and stop the passage of green light. The magenta dye is lacking, it leaks some blue light. The cyan dye is meagre; it leaks lots of green light.

    In a slide film, we must live with this, but a negative film is just a means to an end, we don’t look at the negatives, we use this negative to make positive prints or slides etc. With negative films we can use clever ways to make improvements.

    It was Wesley Hanson of Kodak Labs who figured out how to make an improved color negative film. Hanson added a touch of yellow to the incomplete magenta dye and, a touch of magenta to the incomplete cyan dye. This molded the finished dyes making a film that yielded a more faithful image. The orange tint (mask) is counteracted by the printing process, The mask is composed of two positive images that are superimposed atop the three negative images. It improves the color and contrast of the finished negative. The mask is not uniform orange. It is a positive image, strong orange in the unexposed areas and feeble in areas of high density.

    The hue of this orange corrective mask used is based on the makeup of cyan, magenta, and yellow dyes uses when manufacturing the film. As new and improved dyes are discovered, the color of the orange mask must be adjusted as required.

    A tip of the hat to Hanson
     
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  5. It could be that the Blix or Bleach was exhausted to a degree, used at the wrong temperature, or not sufficiently oxygenated.

    Were the films home processed or lab processed ?
     
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  6. Good points -- perhaps a re-bleach and fix will correct
     
  7. Thanks for the reply. Home processed. I use separate bleach and fix. The bleach or the fixer could have been exhausted. I oxygenated the bleach before I began processing so I don't think it was that. Too many variables to keep an eye on. All it takes is for one of them to be slightly off!

    I try not to mix films in the tank. I believe I read that it shouldn't be an issue, but I still try to avoid it. I went against my unwritten rule on this one and developed this roll of Ektar with a roll of Cinestill. Could that have possibly given me trouble? I'm still going to use fresh bleach and fix next time!
     
  8. I am going to give it a try!
     
  9. That IS strange. But my issue can be seen on the negative itself. I wish I had the Nikon 9000. I'm using an 8000.
     
  10. I understood that; I was just wandering off. The chromogenic film in my case was Ilford XP2. The phenomena has happened occasionally on other rolls and scans, sometimes, as I said indifferent images on the same roll. Only with the C41B&W film however.
     
  11. Would I be wrong in thinking that different manufacturers have their own hue of orange mask ? The masks in my different brand films are never quite the same.
     
    Last edited: Jan 4, 2022
  12. The cyan, magenta, and yellow dye incorporated in C-41 film are in a “leuco” (Greek for white). They remain uncolored until they receive a missing ingredient which causes them to blossom. Hanson tinted the leuco magenta dye yellow and the leuco cyan dye magenta. This combination appears orange. As the leuco dye blossoms, the tint diminishes. The tints thus form two positive images superimposed atop the three negative images. This combination delivers a more faithful image. All dyes used are tweaked as technology evolves.
     
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  13. A big gap between the expiry dates of the two rolls, and the storage conditions of each roll can cause different developing results. But another question, did you use the same brand chemical kit for the two negatives in your OP, and your past shoots ? You're comparing them all, but various brands of chemicals will produce slightly varying results.


    I've used both "Bleach and Fix", and "Blix" ... my preference now is for Blix, it works quite well for me in spite of some prejudices against it. Not only that, every brand Blix kit has done a good job on my films, and the less steps involved for home processing, the better, IMO. Tetenal is probably the best but I've also tried Unicolor and Argentix, which were also pretty good.

    I've yet to try Cinestill, I'll buy some soon enough. It's a powder, so no restrictions on shipping internationally.

    Mixing films in tanks shouldn't be a problem, they all require C41, but I only develop one film at a time because with multiple films the pouring takes longer throwing times out, and I haven't been able to maintain the constant 100 degree temperature throughout the process.

    As a matter of interest, here's the result of a Russian bleach and fix C41 kit, CineC41. Only landscapes on the film were like this. Closer subjects were passable and usable. The orange mask wasn't too bad, much the same as your first neg in your OP. As you say, there are lots of variables to watch out for. The idea is to minimize them and perhaps change to Blix.

    Variables in the development process of this film were: Unknown age of the C41 kit. Not real sure if it was for still shots. Film was expired (2008) but stored well. Possibly the temperatures were changing throughout the process. The bleach and fix were two separate steps, which is something I'm not used to with color neg film - Yet, the orange mask was ok on this film. The kit was cheap, so my expectations weren't all that high, just thought I'd give it a try.
    Panorama sample copy.jpg
     
  14. The dyes are organic (organic chemistry). Organic things change their characteristics quite easily. The C-41 dyes are highly alterable if the pH is wrong. They revert back to a leuco state. The film is a subset of black & white, thus a silver-based image replaced by dye. The bleach step coverts metallic silver to a salt of silver. This salt is soluble in the fixer (may be a combined step). If silver is retained, it veils the dyes. This condition and dye reverted to leuco is reversible by repeating the bleach / fix steps.
     
  15. Awesome explanations Alan, much appreciated!

    One thing I noticed, while T400CN was on the market, its mask was barely orange at all, more like a pale tan. Its successors, BW400CN and Portra BW400 reverted to a deeper orange mask much like standard color negative film making them more difficult for standard darkroom printing. T400CN was somewhat closer to (but not completely like) XP2-Super in that regard.
     
  16. The right-hand example in the OP looks as if it's been incompletely bleach-fixed and has a grey silver overlay to the base mask dye.

    However, colour film varies from batch to batch, and far more so between types and makes. With Fuji generally using a noticeably different mask colour from Kodak.

    A bit off topic, but with most colour negative film being scanned and digitised these days, there's very little need for the mask, since any hue shift or lack of saturation can be easily digitally corrected.

    Here's a digital copy of a colour negative shot ages ago on un-masked Agfacolor.
    _DSC5593-pos.jpg
    Admittedly the colour isn't perfect, but IME it's far better than a lot of the prints I've had returned from minilabs!
     

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