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  1. #1

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    C-41 film base color variability

    How much might I expect the base color of various rolls of the same variety C-41 film to vary? What are the variables that would affect it, or is it pretty much constant and unrelated to things like processing?

  2. #2
    mts
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    By variety do you mean brand/type? There is a definite difference in the mask density and color balance between films of different types. Generally it is my understanding that the orange mask is designed to set neutral grey for clear film, somewhat akin to the white balance of digital processing. If you are starting to print a new film, then you start out to adjust your filtration to provide balance to known grey for clear film base. But yes, there is a noticeable difference in the base film filtration between brands and film types, and the difference can change considerably by deviating from standard C-41 chemistry as, for example, by using scratch-mix alternative formulae especially for changing bleach formulation.
    By denying the facts, any paradox can be sustained--Galileo

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    It may have other purposes/effects but the main purpose of the orange mask is to mask dye impurities.

    The color should generally be consistent from roll to roll of the same type of film if processing is consistent. It can vary considerably from type to type.

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    Thanks for the responses, I guess I could have been clearer. I know that the base color is generally different between brands and types of films. My question is whether the base color is affected by post-manufacturing variables, and to what extent if at all.

    For example, is the color produced by a chemical reaction during development, or is it already there and just waiting to be "revealed" so to speak, like one scratches off a lotto ticket?

    Don't tell anyone I wrote this here () but this is so I can know how often I ought to resample the base color when I'm scanning, as it does add somewhat significantly to the time of my (current) workflow.

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    The purpose of the colored dmin in color negative film is to adjust for unwanted absorptions in the dyes. This is called color masking. It varies with the dye set and therefore a given type of film should be the same, but the dmin can vary widely among different brands of color negative film.

    Color balance is achieved in each film such that with a given dmin, the emulsions are dyed to give a neutral repsonse with its own designed Dmin. Therefore, all color films will print "neutral" with the same general color balance once it is established. I currently print negatives from the '50s to the present day with much the same balance but i get different tonality and color palette.

    If Dmin varies within one batch or brand of film, say Ektar 100 35mm, then the film may be fogged, old, kept poorly or the process may be off.

    PE

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    Awesome, thanks so much PE! Also I just want to say that Ektar 100 is really quite a remarkable, contemporary looking film and I'm very happy to have explored beyond my Portra fortress after almost 10 years. Yay Kodak!



 

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