Aristo V54 bulb, Zone VI controller, and contrast?

Discussion in 'Darkroom Developing and Printing' started by Steve Goldstein, Jan 28, 2007.

  1. I was recently doing some step-wedge testing and noticed
    that anything higher than grade 3.5 looked prettmy much the
    same. Here are the details:

    Zone VI cold light head (Beseler 45) with Aristo V54 bulb, less
    than 2 hours total usage I guess

    Zone VI intensity controller

    Kodal Polymax filters (relatively new, high contrast barely used)

    Luminos Flexicon VC (= Kentmere Fineprint VC, I think), both in
    fiber and RC, also Forte Polymax fiber

    Silverprint Tektol neutral and Tektol standard developers

    The Aristo bulb is supposedly designed to work "better" with VC

    It occurs to me just now (that I don't see any available darkroom
    time in the next couple of weeks, and being Sunday I can't ask
    Aristo) that I normally use my Zone VI controller with the intensity
    set at "F" to give me a little longer exposure at f/8. I can achieve
    stabilisation typically up to K or L once the bulb is warmed up.

    Here's my question - has anyone ever done experiments to assess
    contrast grades vs intensity with the Zone VI controller? If so, this
    could save me a bit of time and paper; if not, I'll do it myself and
    post the results, though it could be a while...


    Steve Goldstein, Jan 28, 2007
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  2. I take it you have the ZVI single tube head and the
    'cold light stabilizer' box with 'lamp intensity' and
    'drydown' knobs.
    Some possible causes:

    1) Papers and filters are designed together: Kodak filters for
    Kodak papers, Ilford filters for Ilford paper ... I don't know
    what filters are best for Forte and Luminos [And Luminos can
    be _anything_, though if marked UK then it is probably
    Kentmere]. I would suggest giving Ilford filters a try.
    Looking at Forte's web site may give recommendations for

    2) Old paper looses contrast. Paper can sit on a dealer's shelf
    for years.

    3) Cold light heads will shift spectrum with temperature, try
    leaving the enlarger on for 1/2 hr before printing.

    4) Cold light heads and VC papers have never gotten along very
    well. However, the problem is usually that no low grades can
    be achieved.

    5) Try developing for 5 minutes. VC and many graded papers
    are made from two or more emulsions with different contrasts.
    If the high contrast emulsion isn't developing fully then the
    print looses contrast though it may have full blacks. Try
    Dektol 1:1 as a check. Some papers and some developers
    have trouble developing fully: Forte and Arista developer
    are a bad combination - after 5 minutes the paper still
    hadn't developed fully. Forte graded will take 5 minutes
    in D-72 [Dektol] to develop to completion.
    Nicholas O. Lindan, Jan 28, 2007
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