I need 2 minutes exposure for a good print in my darkroom

Discussion in 'Color: Film, Paper, and Chemistry' started by game, May 6, 2006.

  1. game

    game Member

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    Hi everyone,
    I am quite new to using a colour darkroom. Altough I have printed succesfully at my school in colour. I have been setting up my darkroom at home, and went printing today.
    I succeeded in getting fine print. But I need 2 minutes exposure to get a print with the right density. I used f 5.6.
    2 minutes seems a bit long to me. I am used to 30 sec. or something, or faster. What could be the issue?
    I have my chemicals at 33 degree celcius, like the manual suggests, and have development time set to 60 seconds, also according to the manual.
    The lens is a fine schneider componon S f1/2.8 50mm.
    One other thing is the paper used. I used kodak ULTRA sheets 8 x 7 inch or something like that. Only is was not stored cold in the store, so the store gave me a big discount. they said it was fine paper to experiment and find my way around in the darkroom without spending to much money.

    Has anyone an idea, on why the 2 minutes?

    THANKS A LOT for letting me know. ALL the best - SAM
     
  2. glbeas

    glbeas Member

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    You didn't mention the filter pack. If you wind up with values on all three colors then you create neutral density which will drag out the exposure times. Reciprocity failure may then exert its influence at that point.
     
  3. srs5694

    srs5694 Member

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    What sort of enlarger and bulb are you using? They vary quite substantially in brightness. For instance, my first enlarger (a Durst C35) required very long exposures compared to my second and current one (a Philips PCS130 with PCS150 color controller). The difference was at least a factor of 4 (two stops), although I never timed it precisely, so that's a bit of a guess. If you're using an enlarger that's particularly dim, that could be the explanation.

    Also, have you done B&W printing with this enlarger? In my experience, modern color papers require shorter exposures than do modern B&W papers. If you're seeing the opposite, it could be your paper or developer is to blame, or perhaps you've got some neutral density filtration in place for color but not for B&W.
     
  4. game

    game Member

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    thanks for the replies.
    I use a DURST m605. I believe it has a 100w halogeen lamp inside. the DURST m805 at school used 16 seconds at f8 for a good density.
    Chemicals are fresh by the way.
    With neutral density filtration you mean, using for example: Y30,M50,C70 instead of Y0,M2,C40?

    Greetings Sam
     
  5. Petzi

    Petzi Member

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    Check if the lamp has metal on the inside of the bulb. It might be old and dim. Also check if it is correctly seated in the lamp holder.
     
  6. Jon Shiu

    Jon Shiu Subscriber

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    Hi, you probably already know this, but you are not supposed to use cyan filtration, only yellow and magenta. Also, when I learned, we were told to keep the exposures at about 10 seconds.

    Jon
     
  7. srs5694

    srs5694 Member

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    I'm not familiar with this model, so I can't comment on it specifically.

    Yes; however, in case you didn't know, something like Y0/M20/C40 would be pretty bizarre. If you're using such filtration, then it could be a sign of a problem with the paper or chemistry -- or it could be that the scene was shot under unusual lighting conditions. Typically, you'll use yellow and magenta but not cyan filters.

    AFAIK, that's just because using all three filters produces neutral density filtration, which has the effect of increasing exposure time, and as a general rule shorter exposure times are preferable to longer ones. On rare occasions it might be necessary to use cyan filtration but not magenta and/or yellow in order to correct for odd lighting or some other peculiar color effect. FWIW, I routinely use all three because my enlarger (a Philips PCS130/PCS150) is bright enough that if I didn't do so, all my color prints would be overexposed. (Although technically I'm not using CMY filtration, since the Philips uses an additive design. I'm really reducing the intensity of the red, green, and blue light sources. Still, it works out to the same thing.)
     
  8. Nick Zentena

    Nick Zentena Member

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    2 minutes sounds very long for a colour print. Even 30 seconds wouldn't be short. I wonder if you've hit recpircotiy failure?

    Try making a print with the lens wide open.
     
  9. game

    game Member

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    1. recpircotiy failure, I have seen that word before (spelled differently) What does it mean?
    2. I have always been thought that when enlarging the lens should preferably be on f8 or smaller. Never fully opened...

    Some more info on the above would be appreciated very much.
    Thanks everyone! Sam
     
  10. ras351

    ras351 Member

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    If this model of enlarger has interchangeable mixing boxes you might check what is installed. A 35mm mixing box will significantly speed things up if a larger one is installed. Also try changing the lamp if you haven't already - given large cyan filtration and long exposure times it may be on the way out.

    Regards,
    Roger.
     
  11. game

    game Member

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    The whole, don't use cyan has slipped me mind actually.... :confused:
    The lamp is realy almost new.
    I will look at my filtration, allthough I am far away from f8 @ 15 sec.

    Game
     
  12. ras351

    ras351 Member

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    I had a new lamp which lasted for about an hour before it died so although rare it's possible it's the lamp. You may be able to tell from looking at the lamp - they tend to get extremely hot (more so than usual) as they fail and you can sometimes see the consequences. The only other possibilities are enlarger/head/lamp alignment, filtration, bad paper/chemistry or a rather dense negative. For comparison Ilfochromes with my 100W enlarger, 6x7 mixing box, 35mm negative with 50mm@f5.6 lens a 8x10 print typically takes around 20 to 30 seconds. With the 250W enlarger and a 35mm mixing box I'm down to less than 10 seconds.

    Roger.
     
  13. Photo Engineer

    Photo Engineer Subscriber

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    A typical 8x10 from 35mm with a 35mm mixing box and a lamp of that wattage would be about 12" at f8 - 16 with a filter pack of 40Y, 40M, 0C. This is with Endura type paper. The keeping should not be a significant factor in this.

    If you are using a combined C,M,Y filter pack then the speed loss would be equal to the cyan filtration plus a bit. So 60 cyan in the beam is about 2 + stops speed loss if there is M and Y filtration. If you are using a mixing box for 4x5 for 35mm you will lose over 2 stops.

    If you were using Ilfochrome paper, I would expect the type of exposure and filtration you are using.

    I use 38 deg C (100F) for 1' with RA-RT developer replenisher in a jobo, or 2' at 68F (20C) in a tray with the RA-RT developer replenisher.

    PE
     
  14. Petzi

    Petzi Member

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    Did you install it? Is it seated correctly?
     
  15. srs5694

    srs5694 Member

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    I believe the correct spelling is "reciprocity failure." This refers to non-linearity in the exposure characteristics of a film or (in this case) paper over time. In other words, a 10s exposure at f/8 (to pick a random value) may not be equivalent to a 20s exposure at f/11 or a 40s exposure at f/16, even though they should theoretically be the same. Modern films are designed to not encounter significant reciprocity failure over common exposure times. I don't know much about the reciprocity characteristics of paper, but the suggestion was that a 2-minute exposure might be running into this limit. The result would be that you might need an even longer exposure than you'd think -- or alternatively, if you increased the light hitting the paper (say, by opening the aperture a bit), you could decrease the exposure time by more than you'd expect -- say, to something less than 30s if you opened up by two stops.

    One other note: Different color layers in color film (or presumably paper) have different reciprocity characteristics. Thus, reciprocity failure can result in color shifts as well as the need for modified exposure in color materials.

    The optimum aperture depends on the lens, but in general it's about 2 stops down from the maximum aperture. I believe the suggestion to try a wider aperture was as much for diagnostic purposes as anything else. If you open up (say) two stops and find that you can then get good results with, say, a 15 second exposure rather than the 2 minute exposure you require now, then you know you've run into reciprocity failure -- either that or there's something weird going on with your lens. Speaking of which, that's another possible source of problems -- check to be sure that the lens is clear and that the aperture blades open and close as you'd expect when you adjust the f-stop setting.
     
  16. game

    game Member

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    Tommorow I will indeed check if the lens is clean. I'll open up the aperture to check repricio.... failure. And will use zero cyan filtration.

    Two things. At first I use 33 degree, maybe I could go higher than suggested by the manual? Then I might get a denser print at faster exposures.
    Second. I have read several times, that I should check on the installation of the lamp. I actually did that myself, but I never figured something could go wrong there, seems really simple. So what could be wrong?

    thanks for all the replys! best regards Sam
     
  17. game

    game Member

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    Allright,
    Today I raised temperature of both blix and development to 37 instead of 33 degree... right now I am at 25s. with f4 and a half. Still not like it should be though...

    What does temperature does?

    And maybe someone could lay down what to watch out for when checking on the lamp.
    THANKS Sam
     
  18. game

    game Member

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    Well,
    I think I might found the issue...
    I opened up the enlarger and the lamp was floating loose in the cabin!?
    It needs to be secured with two screwes, but it wasn't - guess I have not been really carefull when installing the lamp.
    Small problem is that I can't find the screwes anymore... guess I am screwed ....
    in the end I'll fix it, and i'll keep this thread updated for whoever it might help.
    in the mean while the whole temperature thing got me interested.
    I know how to manipulate color, but what are the effects of both development time and temperature? Are they common parameters in manipulating the final print?

    sam
     
  19. Photo Engineer

    Photo Engineer Subscriber

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    I use developer temperatures from 68 deg F (~20 deg C) to 100 deg F (~38 deg C). The time is 2' at 68 deg and 1' at 100 deg. The print shifts on the yellow - blue axis over that range of time/temp., with about the same density overall.

    Blix time is about 2'30" at 68 deg and 1' at 100 deg and I use a wash of about 10' at 68 deg F and about 2'30" at 100 deg. I know this is not the 'real' times, but I have clocked blix and wash action on this paper a lot and it works well.

    PE
     
  20. game

    game Member

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    I can only set my developement time... no blix time

    is that weird?

    sam
     
  21. game

    game Member

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    hmmm, fixed the lamp and right now I am at a nice 5 seconds with f11.
    Thanks for all the help - sam