Can we use the cold light head to print AZO?

Discussion in 'Contact Printing' started by TN98, Feb 4, 2007.

  1. TN98

    TN98 Member

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    I'm trying to find the R40 Bulb but have yet to find one in Bangkok. I'm using the Aristo D2-HI on my Omega D2. Just wonder, anyone using the cold light head for AZO. What is the estimating time if it can?
     
  2. Michael Kadillak

    Michael Kadillak Member

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    As you know, Azo is a very slow paper. You could use your cold light head but the exposure times could be very long. I have no idea because I do not know what effective illumination you could deliver to the paper. You could always give it a try. I use a R40 300 watt bulb and print for between 10 and 25 seconds. I have to believe that in today's global marketplace you cannot get access to a bulb that is consistent with your power delivery. My first reaction is there are a lot of illumination in Hong Kong and someone there must be selling some bulbs. Worse case you could order one from the states and make sure that it is packed well. After all, they are only $5 US.

    There is nothing better then using the right tool for the job.

    Cheers!
     
  3. Alex Hawley

    Alex Hawley Member

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    You don't really have to have an R40 bulb. A regular common light bulb will do. You always but the standard bulb inside a reflector hood to direct the bulb's output. Exposing Azo with a cold light will take many minutes of exposure to accomplish at best.
     
  4. bobherbst

    bobherbst Member

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    Cold light head to print AZO

    Alex is dead-on regarding use of an ordinary light bulb in a reflector. I use a 100 watt soft white bulb in a 10 inch photo reflector hanging 2 feet over the vacuum frame. Exposures for grade 2 AZO are in the 8 sec to 45 sec range. (I have dense negatives...on purpose). It is a little weird at first to be lighting up the whole room during exposure. Using an enlarger will take you 20 minutes or more. I also use a light integrator and a modified photo cell to keep exposures consistent. That became required because my wife would be doing laundry in the room next door and every time the dryer was turned on or off, the light would dim or brighten from the line voltage changes enough to have a big effect on the print values.

    Bob Herbst
     
  5. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    After experimenting with various light sources for Azo, my favorite is a cheap desk lamp from Ikea like this one--

    http://www.ikea.com/webapp/wcs/stor...-1&categoryId=17168&chosenPartNumber=40050451

    With the UV filter removed. It's tall enough for even exposure with 8x10" (and can be easily propped up for larger formats) and exposure times with properly dense negs are in the range of 15-40 sec.

    I've tested to see if it would put out enough UV for albumen printing, and it does put out more than, say, an ordinary daylight fluorescent bulb, but exposure times would be on the order of 8 hours or longer.
     
  6. Jon Shiu

    Jon Shiu Subscriber

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    I have used a cold head for azo. Just remove the lens and cone and lower the head down nearer to the baseboard. I believe times were in the 2 minute range on some older 1960s azo.

    Jon
     
  7. TN98

    TN98 Member

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    Thanks, for all the informations. I think I can find the reflector bulb at 100w and give it a try. :smile:
     
  8. Rich Ullsmith

    Rich Ullsmith Subscriber

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    Great to find this thread, because I am going to try this tommorrow. I thought maybe putting the contact printer right on the neg stage, with the head lifted . . .the will bring the cold light within about an inch of the printer. Just didn't want to defrost a pack of Azo to find out it doesn't work at all!
     
  9. Jon Shiu

    Jon Shiu Subscriber

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    I think the cold light was about 18" from the paper when I tried it.

    Jon
     
  10. jgjbowen

    jgjbowen Member

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    I found that I cold contact print Tri-X developed in HC-110 using a Zone VI cold light with exposures in the 30-45 second range with the head very near the paper. When I switched to TMY developed in Pyrocat-HD the exposures increased to 120 seconds. I found that to be too long and switched to a different light source. I obtained one of the Azo "Cold One" heads and now my times are 9 seconds, with the head at the top of the enlarger! Note: all times quoted are without a lens.
     
  11. Peter Schrager

    Peter Schrager Subscriber

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    light

    when I did this could not find the R40 bulb. Instead use a Sylvania 200Watt bulb
    #S488. I have it inside a small aluminum cone and have the lamp attached to a pulley on the ceiling for convenience if I need to raise or lower the bulb. So far I have it set at 37 inches and it works perfectly. Times range from about 25-50 seconds for grade #2. Hope this helps....(also gives a great suntan)
    Best, Peter
     
  12. Brian Miller

    Brian Miller Member

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    There is also the option of using a conditioning power supply for a computer. I have been using a TrippLite backup/filtering/conditioning supply for over a decade. The voltage coming out is regulated by continuously switching between transformer taps. As the voltage fluctuates, I hear the relays clicking. It takes quite a voltage jump for it to switch over to the battery backup.