Cold light head vs. diffusion head

Discussion in 'Enlarging' started by SchwinnParamount, Jan 14, 2005.

  1. SchwinnParamount

    SchwinnParamount Subscriber

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    Does anybody know what the effects these two heads have on printing? Are they basically the same effect? Are they both better than using a condenser head?
     
  2. Ole

    Ole Moderator Staff Member Moderator

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    I have only used diffuser and condensor, but I will not say that one is "better" than the other. They are different, but not better or worse.
     
  3. Donald Miller

    Donald Miller Member

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    Both diffusion and coldlight heads emit non collimated light. The benefits are less problems with dust and spotting then condensor heads (collimated light). The detriments, in my opinion, are lower local contrast and lower apparent sharpness then condensor heads. I have both types and thus really have no axe to grind on the matter.
     
  4. Eric Rose

    Eric Rose Subscriber

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    I printed with a condenser head for years and then went to a diffusion head. I have just recently got a condenser head for my 4x5 enlarger and want to see what it will do for a series of very gritty photos I am doing.
     
  5. rbarker

    rbarker Member

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    I think it's sort of a squares and rectangles thing. All cold light heads are diffusion heads, but not all diffusion heads are cold-light. :wink:

    Both will produce less contrast than a condensor head, but the cold-light uses a florescent tube (or tubes) rather than incandescent light. Because of that, there are issues of consistency with light output with cold-light heads that are often solved by special timers with light probes that attach to the head.

    Other cold-light users can give you more info. (I use a condenser enlarger.)
     
  6. Tom Stanworth

    Tom Stanworth Member

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    Most agree that cold light and diffusers produce the same approx look and contrast. They reduce surface marks and imperfections on the neg. Cold cathodes are not normally OK with VC, tho some are specifically designed for it. CC heads produce moe bluse light and are therefore fast with graded papers. Condensers produce a more contrsty light with greater apparrent sharpness. Negs should be lower in contrast. I have about a 2 grade difference in my kit, the diffuser being 2 grades less contrasty. I use the condenser when I want grain to be sharp and more obvious. Personally as I shoot mainly landscapes on LF, I prefer the diffuser. If I shot more street scenes I would use the condenser more than I do. They look different, very different IMHO, the condenser being totally intollerant of poor technique/dirty negs, dust etc.
     
  7. Eric Rose

    Eric Rose Subscriber

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    You seem to be talking in circles here old boy.
     
  8. Doug Bennett

    Doug Bennett Member

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    I think it's not a question of which type is better, but which type suits your negatives better.

    After 5+ years of printing with condenser, I tried a diffusion head for the first time last weekend. I tried it on a negative that was fairly dense, and had a wide range of tonal values. This particular neg never would print well on my condenser rig, giving a classic "chalk and soot" look, with blown, featureless highlights. With the diffusion head, it looks stunning.

    However, I then took a fairly "thin" (i.e. less dense) negative, one that had a more comressed tonal range, and printed it under the diffusion head. OK, but nothing to get excited about. So, I'll likely always need both condenser and diffusion.

    The cool thing is that I've now got 5 years worth of negatives that I'd given up on that I can go back to and print!
     
  9. Paul Howell

    Paul Howell Member

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    I agree, one size does not fit all. I use both diffusion and condenser heads on my D 3, and I am now looking a old enlarger that I can convert to a (I know not a true point source) point source type enlarger.

    Regards
     
  10. dancqu

    dancqu Member

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    Diffusion? Are you speaking of a dichroic or of a light bulb
    and diffusers?
    I'm considering the removal of the condensers from my
    Omega B8. With it's single round bulb I've doubts if it
    can do well as a diffuser. Dan
     
  11. Tom Stanworth

    Tom Stanworth Member

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    Not at all, re-read it..........tho its perhaps a wee bit choppy, the facts are correct.

    Diffuser and Cold cathode have a similar look, but are both less contrasty than a condenser. A condenser produces prints with greater apparent sharpness and more visible grain. I therefore prefer diffusers for landscapes and like the sharp grain of a condenser for street stuff. was I confusing, or do you think I have this wrong?!

    Tom
     
  12. SchwinnParamount

    SchwinnParamount Subscriber

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    Good question. I guess I don't even know what a dichroic enlarger head is. So now we have a third type of diffusion enlarger?

    1)Light bulb and diffuser
    2)dichroic
    3)cold light.

    Is that right. As someone said above, the operative feature is 'diffusion' regardless of the actual light source. would that cause all three to have the same effect?
     
  13. lee

    lee Member

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    light bulb and diffuser is like an Elwood enlarger kinda old like mine and me
    Dichroic is a color head with the filters built in and are dichroic filters hence the name
    cold light like Aristo or Zone VI

    essentially they will yeild the same qualities in the print

    lee\c
     
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  15. Paul Howell

    Paul Howell Member

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    I have a D3 with a cold light and Durst with a color (dichroic head) and it seems to me that the cold light is softer than the dichroic head. I print grade 3 with the Durst and grade 4 with the D 3. Maybe its just my perception. But I aslo print grade 3 with the condenser head on the D 3. And there are 2 kinds of condenser type enlarger, point source, bare blub and semi defuse with a frosted bulb. I know that Besseler made a point source head, but I have never seen one on a Omega.

    Regards
     
  16. SchwinnParamount

    SchwinnParamount Subscriber

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  17. Tom Stanworth

    Tom Stanworth Member

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    1. Cold light - uses a tube or tubes. Normally not very suited to VC papers as the light is very blue (therefore giving fast exposures on graded paper). Even adding filters can give erratic spaces between grades and often not the full range of grades. Some specially for VC have different tubes putting out light of different colours. The relative intensity is altered giving teh VC effect (tend to be very expensive). A cold light tube (like a mini floursecent tube) meanders across the whole neg area and is close to the neg and therefore is very diffuse.

    2. Dichroic Head. These heads are normally used for colour and use halogen bulbs emitting light into a diffusion chamber (hence diffuser term used) this finally exits through a peice of diffuse material (normally opal plastic) very close to the neg and so is very diffuse. I dont know the term, but multigrade heads normally use a similar mechanism, but instead of Yellow, magenta and cyan, they use just preset grade adjusters (using Y and M mixers inside) to adjust contrast. Some later Ilford MG heads work somewhat differently I beleive, adjusting the intensity of bulbs putting out light of different colours, so I have been told.

    3. Condensers. They use a light source, normally resembling a normal light bulb. This light shines through lenses which focus it on the neg. The light is very directional and contrasty. The bulb may be large and frosted (less contrasty, tho more contrasty than a diffuse source by far) or small and clear - very sharp and contrasty. A piece of diffusion material can be put above the neg in any of the condenser types (assuming this can physically be done) to soften the light and make it more diffuse.

    Getting even lighting of the neg and reasonably fast exposures are the problems associated with placing diffusion material into a condenser effectively. Some enlarger are designed for this (such as some Durst heads) to broaden the flexibilty of a given head, but DIY solutions may be tougher to get right (with problems such as heat build up, will the plastic melt etc....) I'm sure some have done great DIY diffusers for condensers.

    What you like is personal opinion. If I could have only one, it would be diffuse light every time, tho I prefer to have both. My landscapes improved hugely when I started using diffuse light. If you use smaller formats, getting grain free well seperated skies with a condenser can be tough, but getting the grit and punch into a street scene with a diffuser can also be tough.......
     
  18. dancqu

    dancqu Member

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    "Would that cause all three to have the same effect?" That is an involved,
    complex matter. I'm not sure that they can have the exact same effect.

    First consider the temperature of the light sources, cold light, warmer
    halogen and most warm tungsten. Then there is the shape and position
    of the light source; pointy, bulbous, tubular.

    I'm sure that any of the three can produce excellent results. There is
    one paramount consideration when selecting an enlarger, how well it
    illuminates the negative. Dan
     
  19. SchwinnParamount

    SchwinnParamount Subscriber

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    Mine is bulbous. I shoot 35mm, 6x4.5, 6x7 and 4x5. I have a set of condenser lenses for for the 4x5 and a smaller set which seems to work for 6x7 and down. The cold light head I am considering has an semi-opaque plate of the same diameter as the 4x5 condenser lens. Given that Omega made a set of smaller lenses for small film formats, what do you suppose will happen if I use the large cold light diffuser on small negatives? any ill effect?
     
  20. dancqu

    dancqu Member

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    Those small lenses are used to focus the light onto
    smaller negatives; to intensify the light level. As long
    as you've coverage you're OK. Dan
     
  21. lee

    lee Member

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    point source lights are pretty rare now days. Durst still makes one I think but it is a order item I would bet and not in stock (I'm guessing here)

    Aristo makes coldlight tubes that are closer to the VC paper these days. I have an Aristo VCL 4500 that is a two tube light that is aimed right at the VC paper printer.

    What the photographer needs to do is learn to develop his/her film to match the light source that said enlarger has. All of Kodaks recommended development times for their films were determined to be used for diffusion enlargers. Since condenser enlargers yeild contrastier light, one must soften the contrast of the light and therefore use less time in development of the negatives.

    in answering the last cold light question it will work just fine. Just put the diffusing plex in the bottom of the cylinder and put the light on top of it. Cold lights like to be as close to the negative stage as possible. The plex is not semi- opaque it is Opal glass an is opaque.

    lee\c
     
  22. Helen B

    Helen B Member

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    Um, strictly speaking... condenser lenses focus the light onto/into the objective lens, not the negative. That's why you need different condenser lenses for different formats - but only if the focal length of the objective lens changes (the light needs to be focussed at a different distance from the negative for a 105 mm lens than for a 50 mm lens, for example). Of course, the condenser lenses also need to be physically bigger than the format they are designed for.

    The matching of condensers to objective focal length (and the adjustment of the focal point of the condenser lens) is important if you wish to achieve even illumination.

    Diffusion heads don't need matching to different formats/objective lenses in the same way.

    Best,
    helen
     
  23. Helen B

    Helen B Member

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    ... and nobody's mentioned the so-called 'Callier Effect' yet? But does it exist?

    A good part of the reason why condenser enlargers generally produce more contrasty images?
     
  24. lee

    lee Member

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    Hi Helen,
    I can't prove the Callier Effect exists but I think it exists. There are those that will disagree with that last statement.

    lee\c
     
  25. rbarker

    rbarker Member

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    My old Omega D2V didn't come equipped with Callier ID, so I'm not sure. :wink:

    I've always just thought of the difference as being similar to using a fresnel spot versus a big softbox. The spot (condenser) produces hard shadows (the sharp, contrasty image on the paper), while the diffuser/dichroic/cold-light produces softer shadows due to the light "wrapping around" the film grains.
     
  26. Tom Stanworth

    Tom Stanworth Member

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    It sure does............appear to. The mechanism seems logical enough and you cannot argue with prints compared side by side! My diffuser is very soft and If I can print on G2 with it, the condenser will be running at G0, perhaps even G00. The contrast divide does not seem constant to me either, sometimes the difference is 1 grade, others times more, perhaps th highlight (dense silver) component dictates.