Color Head & FIXED Grade Paper

Discussion in 'Enlarging' started by afrank, May 18, 2012.

  1. afrank

    afrank Member

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    I am using a CLS 66 Color head that doesnt use any of the standard YMC range values 0-130/170.
    My has a maximum of 100. I was wondering if changing Magenta would affect NON Multi grade Paper.
    If so I already have my times without magenta set up, what kind of exposure correction should I use if I dial in 50m or even 100m? If noone knows, how should I go about making tests to find out?

    Thanks in advance!
     
  2. Thomas Bertilsson

    Thomas Bertilsson Subscriber

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    Why would you want to do that? Is there something wrong with good old white light?

    If you add magenta in the light path, you reduce the amount of light that the paper is actually sensitive to. You gain nothing.
     
  3. afrank

    afrank Member

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    Is there no contrast control on normal graded paper with magenta?
     
  4. Thomas Bertilsson

    Thomas Bertilsson Subscriber

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    No. You're better off tweaking your paper developer to adjust contrast. Dektol in one bath, and 120 in another. You can play with dilution too.
     
  5. ic-racer

    ic-racer Member

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    That is correct.
    Best to us no filtration, unless your printing times are too short. Then you can use yellow and/or magenta to filtration to increase printing times.

    Some heads are designed up so that 15cc of filtration approximates one-half stop of density.
     
  6. Bob Carnie

    Bob Carnie Subscriber

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    No... put your head at white light to get the most light output.
     
  7. Bill Burk

    Bill Burk Subscriber

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    Bob's saying no to your original question. Graded paper does not give you different contrast grades in response to changes in color, you only get different exposure times depending on how much "actinic" light gets through (think opposite color of your safelight ... blue).

    If you want longer print times, adding M + Y in equal amounts can cut the light, like a neutral density filter. As IC-Racer pointed out, by design, these are numbered using "as-if densities" without the decimal point, making 15 a half-stop 30 a whole stop etc.

    As Thomas pointed out, changing contrast (often hear it is up to a half-grade change) can be done by changing the developer chemistry. You could also intensify your negatives. You can also dodge and burn to extend darker and lighter tones than a straight print would deliver. I consider all these options when the negative doesn't match the paper I want to use.
     
  8. Bill Burk

    Bill Burk Subscriber

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    I just checked the instructions on my CLS 35... Indeed the calibration of the filters is density... Each division represents 0.01 density.
     
  9. Bob Carnie

    Bob Carnie Subscriber

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    Hey Bill

    If you want to create nuetral density reduction or increase one would use all three filters CMY equally.
    We always used a two bath developer and water tray to soften or increase contrast slightly with graded paper, but even then it was limited.

    Bob

     
  10. DREW WILEY

    DREW WILEY Member

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    No need for netural density. Since most graded paper is blue sensitive, you could just up the value
    of the yellow light to slow the exposure time. But why?
     
  11. Bill Burk

    Bill Burk Subscriber

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    I think you're right, dialing in yellow is probably enough.

    It might be useful in case you run out of f/stops on your enlarging lens and you need a little time to burn and dodge.

    I am always using f/11 and f/22. I don't even know if they are optimum, I am just forced to use those f/stops. (Not with the CLS35, don't know the times I would get from that).
     
  12. cowanw

    cowanw Member

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    Adding cyan is the same as adding minus red. This would be the equivalent of turning your safelights down. Of no usfullnesss in B+ W printing at all. A totally different situation as regards printing colour.
     
  13. afrank

    afrank Member

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    Really want to thank everyone for the comments and helpful advice! And what about using graded paper? Anyone here familiar with that 0-100 scale to achieve grade 4/ 5?
     
  14. Bill Burk

    Bill Burk Subscriber

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    I think you are referring to this insert that says use 150 M if the scale goes to 150 and use 170 M if your scale goes to 170. What they really mean is use Max M and take what you get.

    http://www.ilfordphoto.com/Webfiles/2010628932591755.pdf

    To really get Grade 5, I think you need to add 50 M or 70 M as a filter in the filter drawer (assume your colorhead has one, CLS35 does, and instructions say if you need more density use the filter drawer.
     
  15. afrank

    afrank Member

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    Indeed that is the PDF where I got the ref CMY values. I guess I will just scale my values from the maximum 100~grade 4. Any idea on what scale to use? Log, linear? other?
     
  16. bdial

    bdial Subscriber

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    I did a linear conversion by taking Ilford's full scale values and dividing, worked fine.
    However, no matter what method you'd use, you will need to do some testing. If you want to get to the exact grades, it's helpful if you have a set of Ilford filters, you can make a set of exposures with the gel filters, and another with your calculated settings and compare.

    A much easier method is to treat it arbritarily which is what it is really anyway. Your end points are fixed, that is, you get the minimum possible contrast with full yellow, and max with full magenta. Everything in between is more of one and less of the other. So if your print needs less contrast take away some magenta and add yellow, or the other way around if you need more, what grade you're at doesn't really matter.

    Make some tests, keep track of the filtration settings so you can use them as reference points, then forget about grades and just print, this is the beauty of variable contrast papers.
     
  17. Bill Burk

    Bill Burk Subscriber

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    They are all log scales.

    15 = 1/2 stop, 30 = 1 stop.

    Only reason they give different numbers for enlargers with different ranges is that you have to make different compromises depending on the range you have (or you have more options when your colorhead has a longer range).

    There might be more to it... They may also have done tests with specific enlargers to find optimum values per enlarger.

    But they are all log scales.
     
  18. Sal Santamaura

    Sal Santamaura Member

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    I think this question (and the answering posts that followed it) refer to variable contrast, not graded, paper.
     
  19. Bill Burk

    Bill Burk Subscriber

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    Yes, the topic has drifted into variable contrast paper territory.
     
  20. ic-racer

    ic-racer Member

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    Easy to test. Just decide on a standard set of Y and M values for example #2 grade. Then check the other grades to see if they print at the same exposure. If the print is too light then subtract equal amounts of yellow and magenta and correct your exposure chart accordingly. If the prints are too dark, then add equal amounts of magenta and yellow. That way you can tweak your chart to your enlarger.