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  1. #1
    Murray@uptowngallery's Avatar
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    Hello:

    I am going to build some horizontal cold head enlargers (6cmx9cm thru 4"x5" or 5"x7" and something larger to cover 8x10 and maybe larger 11"x14" because I have huge monochromatic lens that was made for 15"x21" film and I just want to do it.

    1) Low budget

    2) I'm in no hurry

    3) That's just the way I am - if I can build something myself, I try. Sometimes this violates rule #1 above, but I learn something in the process.

    4) If someone tells me something can't be done, that's one more reason for me to try.

    5) A whole lot of other odd reasons we don't have bandwidth for.

    6) It keeps me off the street.

    I have read another post about the evolution of the Aristo light source and
    have some questions.

    I had focussed (haha) on a multi-tube blue fluorescent source of 420 nm (unless I can find an economical serpentine lamp source; not likely) with individual electronic fluorescent ballasts (dimmable) diffused thru white opaque acrylic. I have a foot lambert photometer and between adjusting the output of individual lamps and rear mounted reflectors I'll work on getting even illumination thru the optics.

    Using a lamp with a strong 420 nm spectral component, I am assuming graded contrast paper will work and is still available.

    I understand VC paper is used by somehow determining how much exposure with blue and how much with green. I'm not sure if this is measured and calculated or trial and error. What I don't understand is how the two different emulsions produce different appearance...is one 'faster' than the other and one is for dark and one is for light...kind of like the printing side of Zone method?

    Is it possible to get a decent range of density with blue light only and graded paper (if it's still made)?

    Thank you

    Murray
    Murray

  2. #2
    David A. Goldfarb's Avatar
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    Yes, graded paper is still made, and some of us even prefer it. The older Aristo heads put out a greenish light.

    For 4x5" and smaller, you might just get a Graflarger head that will fit on any 4x5" camera with a Graflok back and concentrate your efforts on a larger head for a bigger enlarger. Graflarger backs can often be found for around $100 or less, and Aristo can even upgrade the tube.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  3. #3
    Loose Gravel's Avatar
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    420nm is very blue. I don't know how "strong" the 420nm is. The graded papers will see it very well, but vc paper will print hard. It will be hard for you to see and focus and dodge if the 420nm is the only light there. Maybe consider some light that you can see if your tubes are too pure blue.
    Watch for Loose Gravel

  4. #4
    Murray@uptowngallery's Avatar
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    Ugh, bad pun.

    The lights I'm considering are Super Actinic 3 fluorescents. They peak at 420 for marine/coral fish tank applications but should have some other wavelengths too...

    Murray
    Murray

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  6. #6
    Murray@uptowngallery's Avatar
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    Hello:

    I've done roughly that...downloaded a few paper spectral response curves then compared various lamp curves...I was eager to try pulsed xenon, but unless I find surplus equipment that's beyond my technical ability and sanity...the electric bill and fire hazard are enough to scare me off.

    I know electronic fluorescent ballasts well enough; I designed some for two years. The standard fluorescent lamp fare, however, seem to have poorly compatible spectra, at least the main components are way off the paper wavelengths.

    The few graded papers I could find data for peaked at 425-450 nm or so. Black light blue lamps are centered around 350 nm with some content in the 400-450 range but most of the energy would be wasted. These lamps are cheaper than the Actinics, however.

    I've got some more ideas to mull over...

    Murray
    Murray

  7. #7
    Murray@uptowngallery's Avatar
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    Next question -

    does photomural roll paper come in graded?

    Thanks
    Murray

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  9. #9
    Murray@uptowngallery's Avatar
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    Thanks...

    I have emailed Tom.

    Clyde's wife or administrative assistant apparently answers his email...the reply to a separate subject inquiry was 'spin' about how he only uses the latest modern technology.

    I took that to mean he was busy (a professional, not a amateur with the time to ponder bizarre ideas) and didn't pursue that avenue.

    Murray
    Murray

  10. #10
    Ole
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    Quote Originally Posted by Murray@uptowngallery
    Next question -

    does photomural roll paper come in graded?

    Thanks

    How big is "mural"?

    Several MACO papers come in rolls of 108cmx10m or 125cmx10m, including both graded and variable, fiber and resin base. Even linen base...
    -- Ole Tjugen, Luddite Elitist
    Norway

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