Condenser to diffusion

Discussion in 'Enlarging' started by michael_r, Aug 16, 2010.

  1. michael_r

    michael_r Subscriber

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    I'm about to upgrade by old Omega B66 condenser to a Saunders/LPL 4550 with a VCCE head. I'm currently working on reprinting a portfolio of 35mm negatives, which will be the first negatives I work on in the new enlarger. I've always read about the differences between diffusion and condenser enlarging, but I've never actually used a diffusion enlarger so I'm wondering if anyone can comment on real world comparison experiences with the following:

    -Contrast: On my condenser setup I am standardized on around grade 1. With existing negatives, can I expect to be on around grade 2 with diffusion?

    -Accutance: I'm a little worried about the accutance factor - will the prints actually appear less sharp from a diffusion setup?

    -Dust spots etc: Does diffusion actually lessen the effects of dust and small negative defects?

    When I attended a John Sexton workshop, his opinion was that my prints would look just as sharp on a diffusion enlarger, and that I would not be sorry, even with small format negatives. However I'm a little confused by this. If diffused light helps hide dust and small imperfections, wouldn't that automatically mean a decrease apparent sharpness? I always thought of it as a zero-sum game, like pretty much anything else in the photographic process - ie you gain something here, and lose something there. It's always a compromise, is it not? If a diffusion enlarger gives you high sharpness, AND reduces the appearance of grain, dust and imperfections, it sort of violates that zero-sum law. And in that case why would anyone not use a diffusion enlarger for 35mm?
     
  2. Jim Noel

    Jim Noel Member

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    1. That is a possibility, but not a certainty. Take the time to print a favorite negative at various contrasts to determining what works for you.

    2. You will not be able to see a significant difference. Edges likely will appear slightly softer, under a microscope, or in extreme enlargements.

    3. Not to the extent many advertise. I find little if any difference her. You still must keep negatives clean.

    In the end, you must practice with the enlarger and find what works for you, not for me or anyone else.
     
  3. michael_r

    michael_r Subscriber

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    Indeed I will obviously still keep my negatives fanatically clean, and will do lots of experimenting with each individual negative to determine the proper contrast (same as I would do with any system). I was just wondering if in peoples' experiences the differences between condenser and diffusion enlargers are as great as one might expect based on what you find in the writings of Ansel Adams etc. I guess I expect not. I'm assuming with older thicker emulsion films the differences were probably greater (more callier effect in condenser enlarging with thicker emulsions, etc).

    Thanks for the reply
     
  4. Jon Shiu

    Jon Shiu Subscriber

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    There is a difference in sharpness, or edge contrast, but for most photographs it will not make a difference in an aesthetic sense. After I switched to a diffusion enlarger, I tried for 2 weeks to reprint a picture of sand and couldn't get the brilliance that I got before with a condenser enlarger. But that was the only photo that was a problem.

    Most pictures will be easier to print on the diffusion enlarger, because the highlights will come in easier and small changes of contrast can be easily adjusted.
     
    Last edited by a moderator: Aug 16, 2010
  5. MattKing

    MattKing Subscriber

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    IIRC an Omega B66 uses an opal bulb. As such, its light source is actually half way between a true point source condenser enlarger and your new diffusion enlarger.

    There will be a difference due to the change in light source, but it won't be as large as you suppose.
     
    Last edited by a moderator: Aug 16, 2010
  6. RalphLambrecht

    RalphLambrecht Subscriber

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    Yes, with very similar tonality.

    Due to the circle of confusion, this depends on the size of the print. In theory, yes, but the harder paper grade compensates for much of it.

    Definitely! Just make sure the negs are clean, and don't let it make you skip the glass carrier!
     
  7. Greg Davis

    Greg Davis Member

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    I made a set of comparison prints for my students using a negative developed for diffusion enlarging that I printed on all grades with both a diffusion color head and a condenser head. I used Ilford Multigrade filters for both enlargers and the same lens so the comparison would only be between the light source. The negative is correct on grade 2 by diffusion, but is most closely matched by grade 1/2 with the condenser, though grade 1 would be OK. I don't see much difference in sharpness, but it is a 4x5 negative printed to 8x10 so I didn't expect any. The condenser head exaggerated the dust more than the diffusion head in my comparison.
     
  8. RalphLambrecht

    RalphLambrecht Subscriber

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    Greg's tests verifies my and other people's experience. Love to see the prints!
     
  9. michael_r

    michael_r Subscriber

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    Yes, glass carriers...a whole other issue I'm still experimenting and wrestling with for 35mm.
     
  10. Sirius Glass

    Sirius Glass Subscriber

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    I ended up with a diffusion head because I bought a dichroic enlarger. I have not seen any reason to get a set of condensers to swap in, if it is even possible. Just clean the negatives and find something else to worry about.

    Steve
     
  11. Greg Davis

    Greg Davis Member

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    Ralph, you wanted to see my prints, so here they are. I put the same filters together for easy comparison and labeled each print with the grade and light source. In case it's too small in the picture, diffusion is on the left, condenser on the right. The prints may have more or less contrast than the screen image since your monitor may not be calibrated like mine, but it will give you a good sense of the relationships.
     

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  12. RalphLambrecht

    RalphLambrecht Subscriber

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    Greg

    Thanks for the effort. It's a good comparison.

    I have a suggestion for when you do this next time. Pick a tone (maybe a highlight around Zone VII or VIII) and make sure to keep the exposure that tone consistent. That will give a more relevant comparison between the pictures. If no tone in the two pictures are the same is harder to quantify the change.

    I attached an example where the density of the white wall in the wood-frame building is constant in both pictures.
     

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  13. Greg Davis

    Greg Davis Member

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    There are tones that are constant. Particularly the skin between my eyebrows, which is what I was using as a basis. The Zone VIII tones blew out very quickly as the contrast went up, so I chose more of a midtone that stayed consistent from print to print and from one light source to another.
     
  14. George Collier

    George Collier Member

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    Greg - which diffusion head did you use? An Arristo V54 lamp performs very differently from an older Aristo lamp.
     
  15. Greg Davis

    Greg Davis Member

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    It is an Omega D5 with the dichroic color head.
     
  16. RalphLambrecht

    RalphLambrecht Subscriber

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    I see, I see!
     
  17. Greg Davis

    Greg Davis Member

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    I have to admit, it was a darker tone than I had expected. I was always taught that the highlights would remain similar as the contrast changed and the lower tones would get even lower (when going up in contrast). I wanted to test Ilford's claim that the printing time was constant when changing filters, so I made the best grade 2 I could, then printed a grade higher and lower, expecting the highlights to stay and everything else move. I found that the lighter midtones matched, but highlights (Zone VIII) blew out, while shadows got very dense when going up in contrast, and everything got muddy when lowering contrast.
     
  18. RalphLambrecht

    RalphLambrecht Subscriber

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    Greg

    Paper curves are non-linear. Hence, exposure during contrast changes can only be constant for a fixed paper density. The ISO standard for photographic papers picks a fixed density of 0.6>base+fog to do that. This is a medium gray between Zone V and VI, and darker than I would hope for. For this density, the Ilford and Kodak 'claims' are valid (see 1st attachment). If you like to calibrate your papers for a different density, you need to make your own tables (see 2nd attachment).
     

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  19. Greg Davis

    Greg Davis Member

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    Thanks, Ralph. I have no plans on changing how I print as it has always worked for me, but my findings contradict, or at least put into doubt, the common saying, "print for the highlights and change filter for the shadows." Doing so, as demonstrated by my prints, would increase the highlight density, as well, if I use the same printing time as per the manufacturer's instructions. The main point, however, is to visually demonstrate the effects of the contrast filters with two different light sources so the photographer (or my students) can choose the most appropriate tool for their work. I have plans for other visual tools, such as a set of negatives developed with no agitation, standard agitation, and constant agitation to show the effects on image density and contrast. I also plan to add to the original batch a set of prints using the color head filtration vs. Ilford's filters vs. Kodak's filters.
     
  20. RalphLambrecht

    RalphLambrecht Subscriber

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    The method is called 'exposing for the highlights and adjusting the shadows with contrast', and it is solid advise. Your findings and prints don't contradict it, because you obviously did not change the exposure to keep the highlights at a consistent density. The manufacturer's claim that exposure does not change with filter changes is not true for highlights. It's true for midtones as demonstrated by your prints.
     
  21. michael_r

    michael_r Subscriber

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    Further to my original post, the brand new LPL 7452 VCCE (Saunders 4550 XL) has finally arrived with some nice customized negative carriers. It was a pleasure dealing with KHB Photografix. They were very helpful. For now I'll be working on reprinting a 35mm portfolio so I got a new 50mm Rodenstock APO Rodagon to go with the new enlarger. It has been a long time since I've needed any new darkroom equipment so I'm feeling that good old "new gear rush", which is fun since it can give you an extra push to get out and make new photographs. Can't wait to start printing with the new setup.
     
  22. jeffreyg

    jeffreyg Subscriber

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    Since Michael appears to be printing with filters and multigrade papers, there is the "luxury" of printing different portions of the image with different contrasts. I have been using an Aristo VCL4500 for years and find that to be a very useful tool and have not noticed any loss of sharpness. I print up to 16x20 from medium and 4x5 format negatives. Sometimes using only a portion of a negative. I started out with a condenser then switched to a cold light and the to the VCL. Once you get used to the new equipment you won't look back.

    http://www.jeffreyglasser.com/