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Thread: Exposure times for color paper and troubleshoting

  1. #1

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    Exposure times for color paper and troubleshoting

    Since I'm socked in by the blizzard, I've been mucking around with RA4 print processing.
    First go round I mixed the chems wrong, the resulting contact prints looked
    dark reddish. I realized that I should have used the 10 liter breakdown when
    I had used the 1 gallon break down, remixed correctly the second time and so far no joy.

    I'm just doing color contact sheets to get accustomed to RA4 processing
    my start point was no filtration ( Omega dichroic head ), high, 10 sec. and the
    resulting prints look the same as with the incorrectly mixed chems,
    muddy dark and reddish.

    Is there a start point for exposure times and filtration any one can share ?
    Any idea as to why the prints look muddy dark ?
    I'm using Fuji Crystal archive paper.

  2. #2
    ic-racer's Avatar
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    Re: Exposure times for color paper and troubleshoting

    Bad or expired chemistry?

  3. #3

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    Re: Exposure times for color paper and troubleshoting

    I think the chemistry is fresh, I purchased it late last year, I've been trying different exposure times
    for contact printing and I'm getting something, but nowhere near what I was expecting.

  4. #4
    Greg Davis's Avatar
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    Re: Exposure times for color paper and troubleshoting

    Dark and reddish is because of no filtration. Try a starting point of 60y and 60m (never use the cyan). I found color paper to be very fast, so you may need to stop down a few stops too.

  5. #5

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    Re: Exposure times for color paper and troubleshoting

    Greg, thanks for the tip, it's working a lot better now.

  6. #6
    Drew Wiley
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    Re: Exposure times for color paper and troubleshoting

    No filtration says it all. Yes, you have to watch your chemical mixing, temperature, and timing. But at least you're on the right track now.

  7. #7

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    Re: Exposure times for color paper and troubleshoting

    I had initially tried it with no filtration just to see, then I tried a 40y 40M and still got that muddy red
    Greg's suggestion of 60R worked much better.
    What I'm confused at is how the subtraction of color works, I have a Omega D Dichroic head
    and if I set the numbers to say, 60R ( 60y, 60M ) would this mean that I've subtracted 60 of each color ?

  8. #8
    Drew Wiley
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    Re: Exposure times for color paper and troubleshoting

    Not every colorhead is the same in terms of either initial color (unfiltered) or the scale of increments. So you have to fine tune according to your specific colorhead as well as specific control negative (hope you have one), your specific paper batch, and specific time/temp developer standard. Once you have that pegged down, it gets a lot easier. But with color negs, when you ADD yellow, for example, you can think of it either reducing yellow in the print, or increasing the complementary hue straight across the color wheel, namely yellow. Increasing magenta reduces magenta in the print, but increases the complement of green. The paper itself is balanced to "see through" the orange mask in the original negative, so you don't need to worry about that when using typical RA4 paper intended for optical enlargement.

  9. #9
    Drew Wiley
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    Re: Exposure times for color paper and troubleshoting

    oops.... increasing yellow on the colorhead, increases BLUE in the print. Sorry for the typo.

  10. #10
    ic-racer's Avatar
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    Re: Exposure times for color paper and troubleshoting

    "Subtractive" and "Additive" are terms frequently applied to the colorhead control function. This function is independent of your printing process of negative to negative or positive to positive.

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