bad condenser lenses

Discussion in 'Darkroom Developing and Printing' started by PGG, Jan 14, 2005.

  1. PGG

    PGG Guest


    I believe my Omega DII has a bad set of condenser lenses. I've tried
    cleaning both pieces of glass and swapping them, but I still get a few
    white spots on my prints. In fact, I can even get the spots to appear,
    without any negative, on my baseboard by adjusting the focus. Another
    reason I rule out the negative is that the spots appear in the same spot
    across different negatives.

    I've examined both pieces of glass under a strong light. There are no
    surfaces scratches or marks. About the only think I notice is a few tiny
    bubbles inside the glass. I imagine this is what is causing the spots,
    but I'm really surprised. There is also a tiny chip on the edge of one of
    the edges, but unless it is diffracting light, I can't see how this is
    affecting anything.

    I have a chance to buy another set from a local guy. Before I do so, is
    there anything else I should look for?

    The enlarger bulb is the frosted type and should be correct.

    PGG, Jan 14, 2005
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  2. PGG

    Jim Phelps Guest

    Have you tried rotating the condensers (I would guess there's a way, but I'm
    not familiar with the enlarger). If the spots move when you rotate the
    condensers, then you're probably right. Move one at a time, turning it 90
    degrees and see if the spots move 90 degrees as well. If not, then it's got
    to be something else like the enlarging lens or glass in a glass carrier. A
    wild guess, but it could also be a hole in the camera shutter curtain. You
    didn't mention what format you're using, but you can analyze this
    possibility further.

    I have a bubble in the condenser in my Beseler. It creates a bit of uneven
    light in certain formats, but never a full white spot. A quick way to check
    is tape a piece if drafting paper to the bottom condenser and see if the
    trouble disappears. This will make a diffuser out of the condenser (to some
    degree) and will help in locating the problem.
    Jim Phelps, Jan 14, 2005
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  3. PGG

    f/256 Guest

    I don't think bubbles inside the glass will be created other than during the
    making of the condenser lens, so if you didn't have problems before and now
    you do, there must be some other reason(s). As suggested already, rotating
    the lenses 90 degrees is a good way to tell if the problem is in the
    condensers or somewhere else.
    I think that a bubble inside does not diffract light, it will refract it,
    You already answered your question within your post: look for chips, bubbles
    and scratches. I'd also ask for 2 days money back if not satisfied, or if
    the guy has a similar enlarger, ask him to let them try the condensers in
    his enlarger. BTW, small chips at the very edge of the glass will not
    affect the evenness of light.
    Is it an enlarger bulb? or is it a regular frosted bulb? if the latter,
    look if it has lettering at the bottom, if it does that maybe your problem,
    besides you should use a enlarger bulb not a regular bulb, even if it
    doesn't have letters on it.

    f/256, Jan 14, 2005
  4. PGG

    ibarakicho Guest

    I had the same problem with a cheapo condenser 6 x 6 enlarger that I
    was using during a year in Japan. Went down to the hardware store and
    got a piece of translucent plastic and cut it to fit the condenser
    housing, placing it at the very bottom of the stack, so it was closest
    to the negative. The improvement was dramatic, sort of like having a
    cold light, only not cold. The change was much like having a cold
    light: contrast was a bit softer, and dust on the condensers and
    negative was much less of a factor.
    ibarakicho, Jan 15, 2005
  5. message

    Its quite possible for flaws in the condensers to show
    up on prints but you should be able to see them on the
    baseboard. Try focusing a negative on white paper and
    removing the negative. Since you know where to expect the
    spots examine the open gate image on the baseboard to see
    what is causing it. Stop down the lens since this will tend
    to focus and exagerate the spots. Sometimes moving the lens
    toward the condensers will focus their surfaces making any
    blemishes very obvious.
    The glass used for condensers, at least in Omega
    enlargers, seems to be quite brittle. It will develop small
    chips on the suface if the two condensers are allowed to
    come in contact during cleaning.
    I would try cleaning the condensers with dishwashing
    detergent and warm water. That should get nearly anything
    off. If not try any of the "streak free" cleaners on the
    market. 99% Isopropyl alcohol will take off oil, grease,
    etc, that the soap may not remove. There isn't much that can
    be done about scratches and gouges. Chips at the edge should
    have little or no effect.
    Small defects can sometimes be hidden by reversing the
    postion of the condensers.
    The lamp should be a special enlarging lamp. These have a
    coating of very diffusing material and are much more diffuse
    than a reading lamp. Also, the makers name is on the neck,
    not of the end of the bulb. The correct lamp is a No.
    PH-211, these are still made and should be available through
    photo supply houses like Calumet or Freestyle.

    If it turns out to be the condensers you can get
    replacements from three sources:
    Harry Taylor
    Classic Enlargers
    145 Jeanne Ct.
    Stamford, CT 06903

    203 329 9228

    Another source is Bob Watson. Bob does not have a web site,
    you can reach him at:

    I believe that new condensers are available from
    Omega-Satter, but they are probably quite expensive.
    Richard Knoppow, Jan 15, 2005
  6. PGG

    PGG Guest

    To follow up, yes, the spots are indeed caused by the condensers. I turn
    the condenser 90 degrees, the spots on the baseboard move 90 degrees. I
    scrubbed the lenses with windex too.

    I'm quite surprised that a few bubbles in the lenses cause this.
    I plan on buying another used set and hopefully, of the 4 identical glass
    pieces, I can find 2 that give me spot-free prints.

    As to why I'm just noticing this, well I've only starting to print 4x5"
    negatives recently.
    PGG, Jan 16, 2005
  7. PGG

    RWatson767 Guest

    Richard et al.
    Another source is Bob Watson. Bob does not have a web site, > you can reach him

    Richard Knoppow

    Thank you for the kind words.
    Bob AZ
    RWatson767, Jan 18, 2005
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