Lamp WAY too bright - Prints too dark

Discussion in 'Enlarging' started by Gary Grenell, Dec 10, 2004.

  1. Gary Grenell

    Gary Grenell Member

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    Having bought the Fujimoto 450 M enlarger (see this Forum), it is beautiful. But I'm having a problem. My exposures in printing are far too short. I am stopped down on the enlarging lens to f.11. I am using a enlarging lens 80 mm lens. I am using Agfa Multicontrast paper. My developer is Dektol 1:2. Yet still, I cannot expose for more than 5 seconds (f.11) without having a black print (extreme overexposure in the enlarging). I have not replaced the lamp that comes with the enlarger or tinkered with it in any other way.

    This is a dichroic, dedicated VD enlarger.

    http://www.jobo-usa.com/products/fuji450mm.htm

    The light source is a 250W Halogen bulb.

    Any ideas or suggestions?

    But wait...I come back to edit this post....I've fiirgured this out!! Wrong diffusion chamber! The enlarger came with the 4x5 chamber and the salesperson told me that's all I needed, but he was wrong....there IS a medium format chamber as an accessory.
     
    Last edited by a moderator: Dec 11, 2004
  2. clogz

    clogz Subscriber

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    Had the same problem: the lamp (halogen) started burning brighter and brighter and then gave up the ghost.
     
  3. jon koss

    jon koss Subscriber

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    Not sure if you are totally set now. If not, have a look at the following dimmer:

    http://www.aristogrid.com/prod02CA_750.htm

    Best $100 I ever spent. Once you've had this, you may never go back...

    JC
     
  4. Joe Symchyshyn

    Joe Symchyshyn Member

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    Changing the mixing box usually makes things even brighter!! I'd say stick with the 4x5 version and forget it.

    As far as I knew, the mixing boxes function was to focus the total amount of light into the area required by the negative. If you move to the smaller mixing box, you'll take the light over the larger area and intensify it further.

    My suggestion would be to stop the lens down further... Try 22 (if you have it).

    What about throwing in some neutral density (filter?) into the mix to cut the light down?

    joe
     
  5. Gary Grenell

    Gary Grenell Member

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    Yes...you're correct...I now realize that the other mixing box (smaller would intensify the light even more). In stopping the lens down further (all the way down) to f.22 I am afraid I would be out of the "sweet spot" of the lens. The idea of the neutral density filter worries me. Where does it go? Is there already not a neutral density filter in the mixing chamber that works as I go from VC grade to VC grade?
    What about a longer enlarging lens? What about going from an 80mm lens to a 120mm lens? That would force me to raise the column of the enlarger and have the light source further away thereby increasing the time. But what about my basic premise that a 5 second exposure is too short? Does anyone disagree with that? Perhaps I should just live with that 5 second exposure? Thanks...Gary
     
  6. Gary Grenell

    Gary Grenell Member

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    I looked at that Website. It says that it is for Cold Light heads and I have a dichroic head. It also says that it is for 750 watt inductive power. Mine is 120 V A.C. With a 240 Watt Halogen lamp. Is that compatible?
     
  7. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member

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    If you put a ND filter in the light path above the diffuser it won't have any negative impact on image quality, and you can use lighting gels, which aren't too costly. You could also put a normal optical quality ND filter on the enlarging lens, if that's more convenient.

    Some enlargers give you the option of using a more or less powerful bulb. Can yours do that?

    As far as the exposure question goes--if you want to burn and dodge, 5 sec. is too short. If you want to produce a large volume of prints quickly with no manipulation, then 5 sec. is great. My impression is that Fujimoto enlargers are aimed more at labs that are interested in volume, so it might be that they just have a powerful light source for that reason.
     
  8. Bob F.

    Bob F. Member

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    Unfortunately, dimming a halogen lamp will drastically reduce its life - it really needs to run at full temperature to work correctly.

    Are you dialling in the grades on the colour head or using separate filters? If you are dialling in the grades, are you using an equal exposure time system where you use both Yellow and Magenta settings for each grade - this introduces a useful degree of ND.

    Alternately, if you are using separate filters, dialing in the same amount of Yellow and Magenta should act as a ND filter. Cyan has little or no effect as it subtracts Red and B&W paper is, of course, not sensitive to red in the first place...

    I suspect a ND filter beneath the lens is the simplest way to go as you can simply remove it when making larger prints.


    Good luck, Bob.
     
  9. Gary Grenell

    Gary Grenell Member

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    I think that the ND filter in the lens probably makes the most sense. I will speak to JOBO on Monday...thanx.
     
  10. Nick Zentena

    Nick Zentena Member

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    Slower paper? How are your negatives? Using the right light box you'd gain something like 1 stop in light. I'm a little suprised that your times are that fast with just 250watts.
     
  11. Bruce Osgood

    Bruce Osgood Membership Council

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    The color head should have dial for Cyan filter. You might try Cyan as an ND filter. I've heard it works, never tried it myself.
     
  12. Nige

    Nige Subscriber

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    You don't say what size print your trying to make. Little prints will mean fast times.
     
  13. Ed Sukach

    Ed Sukach Member

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    I would be careful in the placement of a ND gel. Things get HOT in there, and melting/ burning, etc., can cause an awful mess.

    What enlarging lens are you using? Most - Rodenstock, Schneider, probably Nikon, and others, will accept screw-in filters; and ND glass filters, all the way to X10 are readily available, and relatively inexpensive.

    As for the "sweet spot" ... usually the "optimum" aperture will be in the center of the aperture range. However this is only a design "target" ... many other criteria are included in the design of any lens. The apertures are there for a reason ... and *NO* enlarging lens, other than some coke-bottle jury rig, is going to be noticeably worse at either the extreme of the aperture scale. I am more of a "fussy perfectionist" than most, but using all of the apertures possible in an enlarging lens is something I do not worry about.
     
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  15. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member

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    You know, if this thing is really way the heck too bright and you're mainly interested in small prints, you may be able to print on Azo with it.
     
  16. Gary Grenell

    Gary Grenell Member

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    THANK YOU ALL I think I'm getting the picture

    Thank you all for helping me thing through this...what a great forum, and taking the time to help a new forum member is great!

    A few you you have asked questions I will answer:
    The enlarging lens is a Rodenstock Rodagon N APO 80mm.
    The prints are 9 inch square (from 2 and a quarter negs).

    After having read all you have said, my solution is this: I will purchase the best screw in, below the lens ND glass I can acquire, I would imagine that
    B + W or Leica or Nikon glass is the best. I will also not worry too much about stopping down all the way, i.e. f.22 on this lens, if need be. Probably, alignment is more critical than stopping down to the minimal aperture.


    Unless anyone has any other ideas, this is my plan. By the way, my website for my photography is www.grenellphoto.com

    Gary Grenell
    Seattle
     
  17. Bob Carnie

    Bob Carnie Subscriber

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    Hi Gary

    I agree with Joe and others , Put a nd filter into the mixing box.
    As well I like my apeture to be 2 fstops from wide open with a 10 - 15 second exposure with glass carriers. that is the sweet spot that I have found for the work I do.
     
  18. geraldatwork

    geraldatwork Member

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    I am not familiar with this enlarger or light source. From the link it looks like a quality enlarger. But all of the "rigging" to turn it into an enlarger with normal exposure range doesn't make sense to me. Something has to be wrong. You shouldn't have to stop it down to f22, add neutral density filters,devices to reduce electricity or use special slow paper just to achieve what I get with my cheepo Saunders/LPL D7600 enlarger. With a 6X6 negative, 80mm lens, dialed in filtration of 3 contrast and enlargement of that size I get a 12 second exposure at f 8 or 11 depending on the negative.
     
  19. jon koss

    jon koss Subscriber

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  20. Paladin

    Paladin Member

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    Dimming halogen lamps

    the mechanism that makes a halogen lamp useful is that the filament surface is supposed to reach a boiling temperature. the halogen, usually iodine, that is added to the filament in controlled amounts is supposed to allow some of the metallic filament molecules fill the valcuum in the bulb and condense or sublimate back on the cooler ends of the filament to start this cycle over again. if you have ever replaced a halogen bulb in a flashlight that was dark or silvery in appearance that is exactly what has gone wrong, using a halogen flashlight with low batteries is the fastest way to kill a bulb i know of. the entire envelope that contains the filament must be hot enough to keep the vaporized filament molecules as a vapor. the sublimation happens at cool spots and if the glass is cool enough then the molecules will condense there rather than where they have the strongest affinity to condense on the cooler ends of the filament.

    common incandescent bulbs do not suffer this fate as they do not operate at such high temperatures to start with. putting a dimmer on a halogen bulb can be an effective way to control light output in the top third or so of it's peak output, but much lower than that will make this halogen cycle fail, the bulb will grow darker and it will fail as the filiment boils away. if you need less light, the preferred method is to use a lower wattage bulb rather than use a dimmer.

    the standard bulb that fits this enlarger is an ANSI standard ELC bulb, the only thing i can find that comes close in a lower wattage is the EJL bulb that is 200 watts. how long this will last is another story since your fujimoto enlarger has a ballast that feeds the HID (high intensity discharge) ELC bulb. sounds like you need to concentrate on the ND filter option rather than risk voiding the warranty or frying the power supply/balast of your enlarger. or revert to something old and simple like an omega D2v that uses a low tech 75 watt opal lamp.

    another thing to investigate is simply calling the importer of Fujimoto enlargers and ask them is there is a lower powered bulb recommended for your enlarger. that might border on blasphemy sort of like reading the manual, but it's worth a try.

    sorry to be the bearer of bad news.
     
  21. Bob F.

    Bob F. Member

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  22. Gary Grenell

    Gary Grenell Member

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    The Final Outcome

    Now, after a few months, I have a final outcome. I bought a B+W netural density filter and put it below the enlarging lens (screw into the lens mount). That cut down on my light output sufficiently. My initial exposure times with the APO Rodenstock 80mm lens are about 25 seconds at f.8.5-f.11. There is always some subsequent burning or dodging. Enlargments are 9x9 inches (image size) printed on 11x14 paper. This is on Oriental VC fibre paper, cold tone. Souped in Dektol 1:2 with benzotriazole added. THen selenium toned. The prints are looking lovely.
     
  23. GeorgesGiralt

    GeorgesGiralt Member

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    Hi Gary !
    If the bulb is too bright, get a less powerfull one... This may sound like a joke, but it worked for me. I replaced a 100W halogen by a 75 W and it was fine... Pay attention to the bulb voltage and mechanical details... So speak to the LPL importer to choose the correct bulb.
    What controls do you have on the head ? Do you have Cyan, Magenta and Yellow and another knob ? If yes, it could be the neutral density you need .... It is often graduated in stops (30 units density means one stop).
    You may also have the oportunity to put a sheet of white transluscent plexiglass on top of the mixing box, this will eat some light....
    The last solution is to use Bergger, Foma or Forte papers, as they are really slow.
    A color enlarger's goal is to be really bright as color papers (Ilfochrome particulary) are quite slow. So it is often too bright for B&W.
    Hope this helps
     
  24. Gary Grenell

    Gary Grenell Member

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    George,
    I spoke with the JOBO rep (they import the Fujimoto enlarger), and he advised against reducing the lamp output. He said that the balance is set for a particular wattage bulb. By the way, there are no "magenta and cyan" etc. settings, per se, as this is the VCCE model.

    I think that the reason it is so bright is that it really is a 4 x 5 enlarger, and most folks will be printing with their lamphead raised up many more inches than mine. The bright bulb will keep their printing times reasonably low (even though it makes my 6x6 printing times too high.

    THanks for your thoughts.
    Gary
     
  25. dancqu

    dancqu Member

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    I don't dodge or burn. I don't like to go under 2 seconds.
    I was at 1.4 and 1.6 seconds at f16 a few days ago. Dan
     
  26. photobackpacker

    photobackpacker Advertiser

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    I think you are on the right track. I print MF with a 100 mm and LF with a 150mm. I just checked it out - using a 6x7 negative and focusing for an 8x10 enlargement, my light source elevations with the 100mm and 150mm enlarging lenses was 57cm and 86cm.

    If you are bothered by adding another piece of glass to the image path in the form of your ND filter, you could go to a longer focal length enlarger lens. This will raise up your light source and will extend your exposure times significantly. If you know someone with a 100 mm lens, try it on your enlarger. 100 mm is a very viable lens for MF and you will gain distance between your easel and light source and lengthen your exposure times.