below the lens filtering

Discussion in 'Darkroom Developing and Printing' started by Matt Clara, Dec 28, 2003.

  1. Matt Clara

    Matt Clara Guest

    Is this in any way inferior to a filter drawer system where the filter is
    held above the lens?

    Another thing, as I'm shopping around for a 6x7 capable enlarger, I've
    spotted the Belseler Printmaker 67. At B&H they indicate it has a below the
    lense filter holder, but when you look at the specifications, there's a
    filter drawer listes as 'internal, for 3 1/2 x 3 1/2" filters'

    Does this mean it offers two systems?
    Is this common?
    I see the Beseler 23c II seems to only have a below the lens system--is that
    correct?
     
    Matt Clara, Dec 28, 2003
    #1
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  2. Matt Clara

    Mark A Guest

    Almost all enlargers have a very small "below the lens" filter holder that
    comes with a red filter. Very few people use the supplied red filter or the
    holder. Those that do use a below the lens VC filters often use a different
    holder that is specifically made for the VC filters.

    The 23C has an above the lens filter in the original condenser head. When
    looking at the head, you should see the hinges where the filter can be
    placed. If one using some other head (cold light, dichro, etc) on the 23C
    then you obviously will not have the filter drawer.

    The filter in the 67 head is placed between the condensers and gets fairly
    hot due to the proximity to the bulb. Make sure that you get the filter
    holder (if it does not come with the enlarger).

    If you buying new, and can possibly afford it, I would go for the new
    Beseler VC head on the 67 or 23C III. Saunders also makes an excellent VC
    head.
     
    Mark A, Dec 28, 2003
    #2
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  3. I think what Mark probably meant to say but forgot to is that yes,
    above-the-lens filtration is better than below-the-lens, where defects in the
    filter can have more effect on the image.
     
    David Nebenzahl, Dec 29, 2003
    #3
  4. the 23c has an above lens drawer for filters. Below the lens can denigrate
    the image. The 23c does have a red below the lens to position your paper,
    its not a good idea to use due to light scatter fogging the paper.

    Sheldon Strauss
     
    Sheldon Strauss, Dec 29, 2003
    #4
  5. Try a print with and without a filter below the lens and compare the two
    for resolution. I have not found a noticeable difference when using the
    Ilford filters, which are specified as suitable for use below the lens
    as well as above. I have high quality enlarging lenses that I use mostly
    at optimum aperture.

    If the enlarger has a filter drawer, use it. It is much more convenient.
     
    Patrick Gainer, Dec 29, 2003
    #5
  6. Matt Clara

    Norman Worth Guest

    The main issue to remember is that the below lens (or below negative)
    filters must have good optical quality, while those used above the negative
    just need accurate color. Above the negative filters cost less as a
    consequence, and below the negative filters require more care.
     
    Norman Worth, Dec 29, 2003
    #6
  7. Well said. You have to keep the latter cleaner; fingerprints and dust are
    more likely to affect your image than with above-the-lens filters. Still,
    below-the-lens filters work pretty well if that's all you can use.

    Jim
     
    Jim MacKenzie, Dec 29, 2003
    #7
  8. All the dodging and burning I am aware of is done below the lens... No one
    is getting their shorts in a wedgie over that...
     
    Dennis O'Connor, Dec 29, 2003
    #8
  9. Matt Clara

    Matt Clara Guest

    With filters some light passes through and picks up characteristics of the
    filter, but when I dodge and burn I block light altogether.
    Unless some dodging and burning is done with filters?
     
    Matt Clara, Dec 29, 2003
    #9
  10. Given that the best we can resolve is in the ~ 10 lppm range on the print,
    which is 4 to 8 times less than a good negative, the slight degradation of a
    below the lens filter is absolutely invisible...
    And, yes I do variable contrast burning of specific areas of a print with
    below the lens filters, above lens filters, my hands, preflashing, tip the
    easel, burn the corners - shucks, I'll even say a prayer over the damned
    thing if it gets me the image I want...

    Cheers ... Denny
     
    Dennis O'Connor, Dec 29, 2003
    #10
  11. Matt Clara

    Matt Clara Guest

    I've obviously a lot to learn!
     
    Matt Clara, Dec 30, 2003
    #11
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