blue tint film base - increase contrast in vc?

Discussion in 'B&W: Film, Paper, Chemistry' started by el wacho, May 21, 2008.

  1. el wacho

    el wacho Member

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    had a look around apug and didn't find anything addressing my curiosity.

    is my logic flawed in thinking that the blue tint in arista.edu ultra films increases the blue content in the light that hits vc paper? i'm also using pyrocat hd - is the stain nulified somewhat? and if so, will an attempt to colour correct ( increase the yellow.. #8 ? ) improve things?


    thanks,
     
  2. Konical

    Konical Subscriber

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    Good Evening,

    I think this is the renamed Foma 200 film which I have also used. I haven't noticed that it prints any differently on MG paper than other films which are much more neutral in color. No tests; just casual observation.

    Konical
     
  3. fschifano

    fschifano Member

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    It looks blue, but I'm pretty sure that the base color is cyan. Red will be filtered out, but blue and green pass.
     
  4. r-brian

    r-brian Member

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    I've developed a couple rolls of the Arista.edu Ultra/Foma 100 and it definitely has a blue base. I haven't printed any of the negatives, just scanned them so far.

    But, I did develope the first roll in DiXactol, a yellowish-brown staining developer. The negatives came out green, yellow + blue = green. You may want to think twice about using pyrocat as your developer.
     
  5. MartinP

    MartinP Member

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    The amount of blue wavelengths in the light going through a "blue" filter will not be increased. Instead the other wavelengths are absorbed to some extent, especially the complementary colours - resulting in a light which appears to be relatively "blue" compared to what it was before going through the filter. Of course, there is nothing magic about "blue" colours and the same principle holds for filters in general.

    So the answer to the question was no, it will not increase the amount of actinic light. However, the different emulsions in VC paper react to"magenta" and "yellow" filtered light, so that could be affected by the blue colour as the dark yellow wavelengths will be reduced slightly.

    The very slight colourcast of the negatives would most likely produce no appreciable effect at all though. You could also make a test-strip across the contrast grades, both with a piece of "blue" film base in the neg-carrier and with a neutral piece, to see if there is any effect ?