Density dial on colour enlarger

Discussion in 'Film and Processing' started by curtis_lowe, May 27, 2009.

  1. My colour enlarger has the three colour dials plus a density dial. I know when colour printing how the colour dials change the colour of my prints but I'm not sure how to use the density dial?
     
  2. The enlargers (Omega, Bessler) I have worked with have a low and a high setting, plus a "white" setting, on a separate switch from the color filters. It changes the intensity of the light through the filters. Does that happen with your density dial? With the two I mentioned above, low is half the light of high, so if I use low, I should increase my time by a factor of two for the same effect. The "white" means the filter pack is not engaged.
    Why would I need this? Well, if I had to focus and I had my lens all the way open but I still couldn't see very well, I can turn up the light. Or, if I have my enlarger head very low to get a small print, and my lens stopped all the way down, but it's still so bright my exposure is like 2 seconds. I might need more time in my exposure so I could change my light from high to low, for instance.
    It's just another way of controlling your exposure time or helping you with your focus.
     
  3. My Opemus colour head has a density dial and I find it very useful. I'm only doing b&w with the head and the exposure times with my head are often very short. I don't want to close the aperture too much, because of diffraction, and the density dial goes up to 60, which gives me 2 extra stops. So it serves like a neutral density filter.
    Regards, Stefan
     
  4. Use the density dial to make small prints without shortening time that causes color shift or stopping the lens down that causes diffraction.
     
  5. I thought that maybe the density dial was adjusted in relation to moving the colour dials to keep exposure times constant, would that be right?
     
  6. That seems like a good idea Curtis. My density increments have been pretty big so that wouldn't work for me. The color filter pack changes are usually in 10% or 5% increments. I think if I were you, I'd find a manual for this enlarger and see what it says about the scale of the density dial, and how it's incrementing. Is one click = 10% more light, for instance?
     
  7. Not sure what you've got there, but on a Durst, the density dial doesn't move the color filters at all, but instead moves metal shutters in front of the lamps to atenuate the light. This is an advantage in that one can make longer exposure times, expecially when working on small prints or more sensitive materials like duping film, without having to stop down the lens which would destroy the clarity of the image. Times that are too short are less reliable since lamp warm up is an issue, but longer also gives the printer time to dodge and burn. Also, most materials have an ideal exposure range and more or less will change the resulting contrast and color. On an enlarger without a density dial, one can use equal amounts of the three color filters to lessen the light, but since they don't track equally, you need to use an analyzing device to read the color.
     

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