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Re: Using Nu-Arc 26-1ks

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  • parallel_imp
    ... metal halide machine. Results? Vague timing? Liz, I used the Nu-arc 26-1K for years. It is not ideal, but it works. Exposures are longer than with a bank
    Message 1 of 2 , Mar 3, 2008
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      --- In PPLetterpress@yahoogroups.com, "Elizabeth Gross"
      <eahalegross@...> wrote:
      >
      > Has anyone used a Nu-Arc 26-1ks for polymer plates? It is the newer
      metal halide machine. Results? Vague timing?

      Liz, I used the Nu-arc 26-1K for years. It is not ideal, but it works.
      Exposures are longer than with a bank of UV tubes; as I recall it, for
      a solid or reverse I used 125 light units, 250 for a medium image, and
      for finely detailed type 400 to as much as 800 light units. That's
      something like 40 minutes. And exposure times increase as the lamp
      ages. For non-critical images I also made a tube of index stock and
      placed it over the glass to concentrate more light--which also
      broadened the slope of the beard.
      Consider also the glass contact frame--you can't massage out any
      air bubbles as you can with a flexible cover sheet. Matte-emulsion
      film (or a matte plate like Rigilon HX) will improve drawdown. But
      most important is trimming all four edges of the plate so there is no
      lip. (The lip forms on the outside of a cut, and interferes with
      drawdown.)
      When the drawdown is complete, and you can see the Newton's rings
      between neg and glass, every single speck of dust or hair becomes
      visible. Make sure none are in the image area!
      --Eric Holub, SF
      ps-the unit has a vacuum relief valve. Leave it open until the blanket
      is drawn up to the glass, then slowly close the relief valve until you
      get full vacuum.
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