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Thread: cold light head

  1. #1
    frank's Avatar
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    So I finally got my LF enlarger, and I have a few friends telling me that I've just got to start printing on FB paper and get a cold light head for it to make really good prints. The trouble is, I can't see any magic in their cold light FB prints that I don't have in my condenser or diffusion head RC prints.
    I'm really looking forward to this new printing initiative where the same negative is printed by many different photogs from APUG to see different interpretations. Maybe then I will see a difference.
    Until then, what can anyone tell me about cold light heads? I know just a bit: there is an older version that requires an expensive controller, and there is a version meant for VC paper with blue and green tubes in it. I've also read that negatives meant to be printed with a cold light source should be denser than normal.
    (Isn't photography great, there's no end to this learning.)
    Frank
    My blog / photo website: http://frankfoto.jimdo.com/

  2. #2
    lee
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    [quote="frank"]So I finally got my LF enlarger, and I have a few friends telling me that I've just got to start printing on FB paper and get a cold light head for it to make really good prints. The trouble is, I can't see any magic in their cold light FB prints that I don't have in my condenser or diffusion head RC prints.


    Then you need new friends. You do need to develop your film a little longer for cold lights. Maybe only one stops worth really. The fiber issue is one of longevity really. RC is just not meant to last like the fiber paper. Some will argue but it is a demonstrated phenomena. A great majority of galleries and museums will not accept RC for that very reason. For proofs it is ok. I don't want to start a war here but this is the way I feel about it.

    The old heads had a bluer tube in them and when the graded papers ruled the earth that was all you needed. VC paper got better and better and the graded papers started to disappear, the old blue cold light started to need help. Most people I know that had one simply put a 40 y cc filter in the light path and used VC paper. It was better but not great. And the photo gods smiled. Aristo, being a corporation, started to deal with the issue of the graded light and vc paper. First the tube was changed to the V54 light source. This keeps the photographer from having to use the 40 y cc filter which really only slowed the exposure down. You are able to use regular VC filters for VC paper with this light source. Next, they built the VCL4500 head. That is the blue and green light. That brings us to today. That addresses your concerns about cold light heads. One other thing that cold light heads do is hide scratches and dust spots to a degree. That is because of the light that is scattered before it is focused. That all being typed one can claim that if you taylor your negative to the light source you can make an equally excellent print. I have been using cold light heads for many years and I recently used a condenser enlarger and it was a disaster. One last argument is that if you make good contact prints of your negatives, it is virtually impossible to make a print to match the print with a condenser enlarger.

    What I want to know is why don't your friends cold light head prints look good or at least have some magic in them?

    WEll, that is probably more than you asked for but I tend to be that way.

    lee\c

  3. #3
    Les McLean's Avatar
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    Cold light heads are usually not so bright as condensor or diffuse light sources therefore exposure times are longer. The same negative printed on cold light will be about 1 paper grade softer than if printed on condensor. IMO the bit about the density of the negative is total rubbish. Small blemishes such as dust etc on negatives will be less noticeable when the neg is printed on cold light, it's something to do with the difference in the way the light is scattered by a condensor. Another myth IMO, is that you can use a regular cold light to print using VC paper and compensate for the fact that the colour of the light is blue by introducing extra yellow filtration. To print VC you need the green and blue light source like the Zone VI that I use although I understand that Aristo do make a VC light source that is very good but not like the Zone VI.

  4. #4
    lee
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    Les and everyone else if they are not asleep by now,

    Aristo makes the VCL 4500 with the green and blue lights. I agree that this is best way to attack the VC problem. I neglected to mention the Zone VI head because, as an old fart, I forgot. I have printed with the Zone VI and the Aristo heads and both do a very good job. The Zone VI does cover up to 5x7 and that is a very good reason to own one if you shoot 5x7. Be advised that both systems are painfully expensive.

    In zone system language, one would process the film to a density of 1.2 >fb+f with a condenser head and to a density of 1.3 >fb+f at zone VIII. This will account for the one grade softer print with the cold light. The way I see it the bit about density of the negative is not really total rubbish to use your words. If you have a cold light with the old style tube, Aristo will sell you a newer tube (light source) that will be closer to the VC Paper response. It has more yellow in it. This is the V54 light I mentioned in the post above. There were several versions of the cold light tube but the most common (I think?) of the old styles is the V45. That was the one that everyone attempted to use with the 40 yellow cc filters. It is the one that should be replaced unless you can find graded papers you like and plan to use.

    http:\\aristogrid.com

    lee\c

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    I have printed with cold light or dichroic heads for almost twenty years. I always accepted as "gospel" the Ansel Adams "text" on the Callier effect. I recently came upon a study of the quality of light as it relates to enlarging. I have recently been led to believe that the condensor or point light sources will provide the greater degree of print sharpness if all other pararmeters in a comparison are kept intact. In other words if we compare "apples with apples". --No oranges allowed!

    I had never considered the dust that the diffusion light sources were compensating for were also having a similar effect on negative detail. It seems that they do, though.

    Am I about to run out and buy the latest Durst with the Azo head? Nope, don't think so.
    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

  6. #6
    Loose Gravel's Avatar
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    I have printed with the W55, W45, the VC8100, and now the V54. The V54 is the winner here. It is, by far, the brightest of all of these. Printing 5x7 onto 8x10 paper with exposures in the f/22 - 32 at about 10sec on Bergger VC CB. This is at least 3 stops faster than the VC head. It is kind of nice to just turn the knob for a contrast change, but exposures are long, hard to see, and the unit is very expensive.

    The W45 doesn't offer a very good distribution of contrast, even with the yellow filter and although fairly bright, still not as bright as the V54.

    The final straw here is that all coldlights require some kind of closed loop timer or stabilizer. The 'thermo' or heater in the head helps, but is not good enough to provide consistant exposures. Light output of the coldlight tubes is dependent partially on tube temperature. In fact, it is possible in some cases to have part of the tube getting brighter, as another part of the tube gets dimmer.

    Given this and other variables, the dual grid VC heads cannot be controlled as well as the single (V54) heads, because the dual grids have two lamps on at the same time. If they are used in the split printing mode, then a controller will work, but not otherwise.

    If you are going for a coldlight, get the V54. With a controller, I use a Metrolux 2, exposures are consistant to better than 1%, with or without the thermo even on.

  7. #7
    lee
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    I have a Metrolux II with the closed loop system. You are right that the VCL 4500 is slow.

    lee\c

  8. #8
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    Frank:

    I think your friends were partly right. I think you'll find the switch to fiber based paper will be a positive one. I suggest using glossy, and experiment with some warm tone and then selenuim and sepia toning. There are lots of great papers besides Bergger but Bergger is definately one to try. I think once you work with fiber papers you will be hooked, even though they are slightly more work.( washing, mounting etc.)

    As for the enlarger, I have both cold light head and a color head.I use both and they have different characteristics that have many people choosing sides about. Obviously you can make incredible prints with all kinds of enlargers. I have a Zone VI VC and a Beseler.

    One thing not mentioned on the cold head is that you don't seem to have to deal with negative pop which because of the heat on the other types can make the neg "pop" itself out of focus. On the downside they are a little trickier to focus.

    The other controversy you will find is timers. I use a Metrolux II timer which doesn't cound down seconds but counts lux units. It has a sensor in the light head that measures the light output and compensates for fluxuations caused by the bulb and also your electrical circuits. ( I have a heater and a vacuum easel that normally would dim the lights and cause fluxuations in the exposure).

    Other people swear by other styles and methods of timing your exposures.

    My advice -use what you have and can now afford and study other methods while you are learning. But do switch to fiber paper.

    Just an opinion


    Michael McBlane

  9. #9
    Ed Sukach's Avatar
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    Quote Originally Posted by lee
    The fiber issue is one of longevity really. RC is just not meant to last like the fiber paper. Some will argue but it is a demonstrated phenomena. A great majority of galleries and museums will not accept RC for that very reason. For proofs it is ok. I don't want to start a war here but this is the way I feel about it.
    APUG is the *last* place I'd ever expect to see a "war". This place is wonderfully tolerant of differing opinions. Someone just asked me why I was on here.. my answer was, "I can even be *wrong* without having my fingers broken.

    I've developed a preference for one particular paper: Ilford MG Portfolio -- which is "RC" paper. Again, the late and *sorely missed* Camera and Darkroom had an extensive article about the construction and longevity of "Resin Coated" - as compared to "Fiber Based" papers. Two significant differences were that FB has an emulsion applied to a "Baryta" (a form of white clay) support, and, with RC, the emulsion is applied to Titanum Oxide (typical white pigment in oils); and, of course, the polyethelene encapsulation of the (usually) paper fiber base. The emulsions themselves were the same.

    C&D concluded that there was *no* significant difference in longevity between the two.

    Ilford "Portfolio" is in demand here in this area - I've managed to stockpile four or five packages of 16" x 20" (ordered and waited for).

    This is the first time I've heard of a gallery - of any sort - refusing RC prints.
    Carpe erratum!!

    Ed Sukach, FFP.

  10. #10
    frank's Avatar
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    I've reposted this question in the B+W paper and chemistry forum where it is more appropriate.


    Please forgive my ignorance, but what is the relative expected lifetime of black and white RC, FB, colour papers (there are diferent types) and digital prints (again there are different types)?
    I have B+W prints made on RC paper back when I was at university (almost 30 years ago) that still look good, and have spent much of their lifetime displayed on walls, though not in direct sunlight.

    Frank
    My blog / photo website: http://frankfoto.jimdo.com/

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