Aristo Cold Light color

Discussion in 'Enlarging' started by DBP, Apr 15, 2008.

  1. DBP

    DBP Member

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    I recently bought a used Aristo 57HI head for my ancient Solar 57 enlarger. Unfortunately, the head arrived with a broken bulb. Today the replacement bulb arrived. The color from the new bulb seems to be rather green. Is this normal? What effect will it have on print contrast?
     
  2. Nick Zentena

    Nick Zentena Member

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    Green would be softer then blue.

    OTOH it's a balance thing. The light may look all green but may have enough blue to be a "normal" contrast unfiltered. Make a print and see. Or if you've got a step wedge do a test with that to see what the contrast grade is.

    If I remember Aristo has a few different bulbs today.
     
  3. Loose Gravel

    Loose Gravel Member

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    Remember your eye doesn't see blue very well compared to green.
     
  4. ChuckP

    ChuckP Subscriber

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    To me the new V54 lamp for VC use does looks greenish compared to the older lamps.
     
  5. George Collier

    George Collier Member

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    I use an Omega D2 with the newer Blue-Green bulb. As someone suggested, it was developed for VC as well as graded papers (the old HI bulb printed always high contrast with VC papers).
    My experience with it is that a normal contrast neg (that I would have printed on Grade 2 Seagull before will require a lower filter with VC (Ilford or Forte) paper (all references are fiber), something like a 1/2 to 1 1/2 filter. I also find that the contrast (and exposure) changes from filter to filter are not linear with this bulb, so it can be tricky, but you get used to it.
    The lower yellow filters can also result in longer exposures than I think would be normal with a white bulb because of the blueness of the bulb.
    One recommendation I had was to find two theatrical gels - one green and one blue, and use them in proportion instead of the filter set to achieve different contrasts, but I haven't tried this yet. They would have to be inserted above the image path up in the head, which is how I use the filter set, but the idea of split filter printing, which I do a lot of, seems too complicated with this 2 filter arrangement.
    I live with it because I like the qualities of the cold light versus the filament bulb.
     
  6. Dan Henderson

    Dan Henderson Member

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    when I first got my Aristo cold light to replace a really old unit, I thought the light was too green. Then I realized it was actually cyan. I split grade print with blue and green filters (Rosco gels available from Calumet, and probably other places.) It works great for me.
     
  7. George Collier

    George Collier Member

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    Dan - could you elaborate on how you use the green and blue filters?
    My guess is that you balance the time between each to achieve a given grade of contrast. For example, if you want a straight #2 grade, then you would give maybe 10 seconds of green and 10 of blue, and change the ratio for other grades.
    Does this also mean that for split grade printing, for example, if you want a partial exposure at #1 grade, and another at #5, that each one of these exposures would mean 2 exposures, one for each filter, so, a total of 4 exposures for a split grade exposure? (Hope this question is clear.)

    Also, do you know if using these filters instead of a filter set, like Ilford's, results in shorter exposures?
     
  8. Nick Zentena

    Nick Zentena Member

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    Split grade basically ignores grades. You make a print that looks good and it might be 2,1.8,3.14 or 2.5.

    It's basically two exposures. First one then the other. Either high or low first.
     
  9. Dan Henderson

    Dan Henderson Member

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    George: here is how I split grade print: I make one test strip through the green filter, process, dry and choose the lightest strip that has some detail. I expose the entire next test strip for the chosen green time, swap the green and blue filters, and do another test for the blue light on top of the green exposure. Process, dry and choose the strip that gives me the contrast I'm looking for. A pilot print with the tested green and blue times tells me if any minor adjustments are needed, and where I need to dodge and burn. Which is much easier with split grading.
    Dan
     
  10. George Collier

    George Collier Member

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    Thanks, Dan. About the filters - can you give any more specifics? I went on Calumet's site, searched for Rosco and can't find them, unless I didn't recognize what they call them.
    (Went to your site, by the way, and like your work.)
     
  11. Dan Henderson

    Dan Henderson Member

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    George: here are the part numbers for the Rosco Gels from Calumet: RC5083 for the blue and RC5189 for the green. You should be able to use the search feature on their web site and go right to them. Both filters came in 20x24" sheets, so you can cut a number of filters out of each sheet.

    Also, regarding split grade printing, I learned the basics from books, but was really able to refine split grade printing by spending a day in the darkroom with Les McLean. I recommend you follow this link to his web site and find his article on split grade printing: http://www.lesmcleanphotography.com/index.php

    Thanks for the compliment on my site.

    Dan
     
  12. George Collier

    George Collier Member

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    Thanks for the info. I have been using an Ilford set with this bulb (and the Aristo head made for 6" filters) with Forte but will be moving to Ilford MG (both fiber). I feel like the color of the bulb creates conflicts with the filters, possibly resulting in very long exposures, and maybe not good filter performance. When I split grade using these, the 00 exposure can be quite long, and with burning in, and switching filters, a 16x20 can take up to 5 - 8 minutes with all the exposures, and that's from a 4x5 neg.
    Steve Sherman once recommended the two filter system as you use, so I guess it's time to try it.
    Thanks again.