Cyan dial setting on dichroic enlargers

Discussion in 'Enlarging' started by tbm, Aug 2, 2004.

  1. tbm

    tbm Member

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    Can someone help me? Simply put, on dichroic enlargers, is the cyan dial always at one specific setting (zero or another) or is it changed in conjunction with the yellow and magenta dials? Thanks for your valuable help.
     
  2. geraldatwork

    geraldatwork Member

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    Assuming you are referring to B&W printing it should be at the 0 setting.
     
  3. photomc

    photomc Member

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    For B&W printing, on most enlargers all three C,M,Y are set to zero. What may be confusing is you can adjust the settings for different grades..that said, I am not aware of any dichro head that needs Cyan to ever be set...but have no experience with any head other than Beselar. Check the insert that comes with the paper or check the mfg web site for settings (read as guide line).

    Good Luck.
     
  4. Donald Miller

    Donald Miller Member

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    With dichroic color heads cyan is not used because it represents only neutral density to the light path. The only two filtration channels used are magenta and yellow. The yellow channel would be for softer contrast printing and the magenta channel would be for higher contrast. These can be varied in relation to each other or used separately in split contrast printing.
     
  5. jd callow

    jd callow Moderator Staff Member Moderator

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    Based upon the responses the assumption is the question pertains to B&W. I'll assume the opposite.

    For colour printing you can achieve colour balance with any combination of 2 of the three filters: Y+M, M+C, Y+C. My understanding of why Y+M is the preferred choice is because cyan is a denser filter and will add more exposure, but it is just as usable as Y or M.

    At times you may find a neg that requires more red than you have available with Y+M and therefore will need to employ all 3 filters.

    Cyan can not be used as a ND filter in colour printing unless a corresponding amount of M and Y are added. Simply adding cyan will cause the print to be redder. I assume that when printing B&W cyan acts as nd.

    Some enlargers come with a nd dichroic filter.

    Hope that helps
     
  6. Bob Carnie

    Bob Carnie Subscriber

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    If you are printing colour negative there will be times that you will require to use cyan filter to achieve the colour balance you want.(cross process negatives come to mind) This will be in conjunction with either the yellow filter or magenta filter (but not both) using all three filters will only add neutral density.
    For cibachrome printing we generally using the cyan and magenta filters as a starting pack. cfk usually and also the new universal paper.
    For Black and white you should only be using the magenta or yellow filter
    more magenta will increase contrast.. adding yellow will lower contrast
    Bob Carnie
     
  7. Ed Sukach

    Ed Sukach Member

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    Not quite. Depending on how much color correction is necessary, cyan may be added to increase the effect of yellow and magenta correction. I've done a bit of work where the model was illuminated with the light through a color transparency projected with a Hasselblad PCP 80 projector. The bulb in this puppy is rated at something like 3600 Kelvin, but after the light passes through the transparency, that is really no longer relevant. The film used is Agfa Optima 100 - balanced for daylight - 5500 Kelvin.

    Printing is done with all three filters: yellow and magenta are not enough by themselves.
     
  8. Bob Carnie

    Bob Carnie Subscriber

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    Ed
    sorry , for colour negative printing one uses two filters not three as using all three will just add nuetral density. You are right you can use three filters and we would use three if printing with a thin negative and wanted to get the lens apeture and time back to a workable time and optimum lens apeture. Otherwise balances are acheived easily with two filters.
    I believe you are mistaken
    Bob Carnie
     
  9. jd callow

    jd callow Moderator Staff Member Moderator

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    In theory and practice any colour can be attained with the use of only 2 filters. When the third is used you generally only increase density and or the amount of red (if the cyan is the third and it isn't compensated) in the print. There is one exception (that I know of) when a third filter, cyan in this instance, may be employed or needed. That exception is when the range of the other two needs to be eclipsed.

    The thing is though, one or both of the other two filters has to be set to zero so essentially you are only using 2 or 1 filter.
    As an obvious example: yellow is at 0, magenta is at 0 and there is a need for 20 points of red. Other examples where cyan is needed whilst the other two are still being 'used' is when more magenta is required and yet it is already set to 0, adding equal amounts of yellow and cyan would create more magenta; or if yellow is at 0 and yet more yellow is required equal amounts of both m and c would be added.

    Cross processed chromes, particularly fuji, and daylight film shot in harsh man made light (bars or nightclubs) are the two examples that come to mind.
     
  10. Ed Sukach

    Ed Sukach Member

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    OK --- I'll try:

    First... "Been There - Done That ..."

    Most -- if not all modern color negative materials have a built-in color bias... That is why there is a definite "orange cast" (actually, dark yellow) to the negatives when they are held up to the light. This bias eliminates (remember we have to think through the negative - positive frame) the need for a LOT of cyan filtration - in most cases - all of it - in printing.

    If the ambient light in exposure deviates enough from that expected... say a 3600K projection lamp used with 5500K "Daylight" film, the - compliment of cyan - yellow bias will NOT be enough (remember: negative) to eliminate the need for all cyan filtration in printing. There will be a need for more than can be handled by the "bias".

    I've read this a number of times. Terribly "choppy" but it makes sense to me.

    In practice ... I start as usual - using a ColorStar 3000. From the image of a gray card, I'll modify the magenta and yellow filtration - until I run out of room ...I'll be at 00 filtration and still not achieve balance. Next, I'll add 30cc (or so) of cyan, and start all over.
    So far, I haven't failed to "balance out" a negative.

    BTW - this is just one reason I do my own color printing.





    i
     
  11. gainer

    gainer Subscriber

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    Cyan is blue-green. Cyan + yellow in equal amounts will leave green and some neutral density. Cyan is -red. Magenta is red-blue. Cyan + magenta will leave blue and some neutral density. There is usually no need for pure blue or pure green in color printing. I used these combinations once to find the visual effect of red, blue and green on accuracy of the grain focuser. Green or white is the most accurate.