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  1. #41

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    The photographer that I encountered in Chicago, Tom Yanul, uses pulsed xenon in his process camera/enlarger. The pulsing in most pulsed xenon occurs at such a rapid rate that it seems to be a continuous light source. It is an arc type source and the one benefit, for those who want to enlarge onto Azo, is that it has the characteristics of emitting a fairly large portion of it's spectrum in the near band UV that Azo is most sensitive to (350-410nm).

    If Sean wanted to start a secondary business apart from his "day job", it might be interesting to see whether the xenon lamp in his enlarger has enough ooomph to enlarge onto Azo. If it does, I imagine that there are a number of photographers who would love to have a place to outsource medium and even 4X5 negs for enlarged prints on Azo.
    Art is a step from what is obvious and well-known toward what is arcane and concealed.

    Visit my website at http://www.donaldmillerphotography.com

  2. #42
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    thanks for the info

    I might give azo a try. 8x10 negs enlarged to 20x24 on azo might be interesting. I know with contact printing azo the negs have to be fairly dense right? Would this also apply to enlargement?

  3. #43

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    Sean,

    The matter is not so much of density (even though it usually ends up that way) but rather one of the contrast range of the negative. In conventional silver printing on a non diffusion light source (point light or condensor) one would want a negative with the zone viii density of approximately 1.15- 1.20 above B+F. In the case of Azo one would want a negative with a zone viii density of around 1.60 above B+F.

    Enlarging or contact printing would make no difference on the contrast of the negative since that would be a matter of the characteristic curve of the paper used. Azo will hold about 9 stops of contrast compared to about 6.5 for conventional silver enlarging papers.
    Art is a step from what is obvious and well-known toward what is arcane and concealed.

    Visit my website at http://www.donaldmillerphotography.com

  4. #44
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    Quote Originally Posted by Sean
    That's a good idea, lol!


    Does anyone know much about pulse xenon enlarging? I assume that the bulb operates in a strobe light fashion, so am curious if this will pose a challenge with focusing, etc?
    If you've ever used a 45A head on a Beseler you've used pulsed xenon, albeit a bit slow in the pulsing. It's really white light and seems to be very steady in the color temperature though the oiutput can vary a bit due to age, temperature and voltage fluctuation just as any other type bulb. Enlarging meters have no problem reading the output and you should have good speed with the more blue sensitive papers. There may even be a substantial UV output if theres no blocking filter installed- pulsed xenon will give you a sunburn if you are too close for too long. It would be interesting to test a bit of Azo under the behemoths light.

  5. #45

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    Quote Originally Posted by glbeas
    Quote Originally Posted by Sean
    That's a good idea, lol!


    Does anyone know much about pulse xenon enlarging? I assume that the bulb operates in a strobe light fashion, so am curious if this will pose a challenge with focusing, etc?
    If you've ever used a 45A head on a Beseler you've used pulsed xenon, albeit a bit slow in the pulsing. It's really white light and seems to be very steady in the color temperature though the oiutput can vary a bit due to age, temperature and voltage fluctuation just as any other type bulb. Enlarging meters have no problem reading the output and you should have good speed with the more blue sensitive papers. There may even be a substantial UV output if theres no blocking filter installed- pulsed xenon will give you a sunburn if you are too close for too long. It would be interesting to test a bit of Azo under the behemoths light.
    Damm! you might even be able to enlarge pt/pd.....wow..

  6. #46
    Sean's Avatar
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    Jorge can you please make me 500 sheets of 20x24 pt/pd?

  7. #47

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    Quote Originally Posted by Sean
    Jorge can you please make me 500 sheets of 20x24 pt/pd?
    No problem, just make sure I get back the negs and the prints..:P

  8. #48
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    lol

  9. #49

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    Damm! you might even be able to enlarge pt/pd.....wow..
    _________________
    Jorge Gasteazoro.
    There is that French firm that does enlargements doing the Carbon process in color. They use a high output carbon arc lamp (high UV output) from what I understand. Of course one needs to be accepted by them in order to have enlargements made. The only question I would have with enlarging any of the UV sensitive processes is the output of the lamp and the UV limiting barriers in the light path (such as diffusion panels, glass surfaces of the enlarging lens etc). Given that enough UV light is delivered to the paper the process should work.
    Art is a step from what is obvious and well-known toward what is arcane and concealed.

    Visit my website at http://www.donaldmillerphotography.com

  10. #50
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    When do we get the next installment of this installment story, Sean? How was the trip?
    Gary Beasley

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