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  1. #1

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    Compact fluorescent enlarger head?

    I'm in the process of building an enlarger out of an old monorail. I was going along pretty well until I asked the bulb company for help. :rolleyes: I want to use a few bulbs from this company.

    http://www.tcpi.com/

    They tell me only up to 23 watts is rated for a recessed can. But a 12"x12"x18" head [or deeper] is a lot bigger then a normal recessed fixture. Worse most of the bulbs are not rated for use on thier sides. I really want to mount the bulbs on thier side. Pointing towards the diffusion material. I guess I can live with the bulbs being mounted pointing straight up but the heat issue is bothering me.

    Anybody care to speculate how bad the heat issue will be? I figure if I'm stuck with the 23 watt bulb that six bulbs might be needed. The head will be made out of white melamine.

    I'm looking at the 5100K bulbs. They would seem to have less red in the light. Of course it would be nice if the bulb company got back to me on that.

    Worse case I'm willing to use a fan or two but it's funny that the compact bulbs I intially chose to avoid heat issues are now forcing me to use a fan.

  2. #2
    jmdavis's Avatar
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    Nick,

    Have you looked at the 8x10 horizontal enlarger that is in "The Print." I don't know whether you plan on a horizontal or vertical design, but I am pretty sure that you plan on a diffusion head.

    But in terms of the power. 23 watts of cf is more than just 23w of incandescent. Looking at the cf's I use in the house, 14 watts of cf is 700 lumens. Looking at some soft-white incandescents 60 watts is 800 lumens. So these 14 watt cf are equal to around 52 watts of incandscent. This works out to be around 50 lumens/watt for the cf. If your bulbs are 23 watts, that would be the equivalent of 1150 lumens. This should be around 85 watts of incandescent light with only 23 watts of heat.

    If you mount the bulbs on their side, you could vent toward the top with something like a metal light trap.Or you could use a quiet fan. But even with 6 of these, the heat will be less than a single 150 watt bulb with a light output of around 500 watts (~6900 lumens). My math may be off for your implementation depending on the lumens rating of your bulbs. But it should be fairly bright without a huge amount of heat (I have a 200 watt bulb in my D2 condenser head, and a 75 watt in my 23CII).

  3. #3

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    I just glanced at the print. It looks like he had 1800 total watts of tungsten bulbs. I've been trying to scale around what the old Elwoods provided. My understanding is they used either 300watt or 500watt bulbs. With that in mind I think 100 to 130 watts of fluorescent will get me into the ball park. I'm also hoping that by using a 5100k bulb that I'll have less wasted light. The red light the normal enlarger bulb puts out is just not doing much good.

    The heat problem is they don't even reccomend using a 24 watt bulb in an enclosed space. They were supposed to get back to me but that was last week. Right now I'm thinking of adding some 12volt fans. Computer fans maybe. But a sealed box would cause less problems with light leaks -)

  4. #4

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    Considering your stated design parameters, have you considered using conventional F15T8 bulbs? The F15T8BL or BLB bulb would expose all graded papers including Azo. The F15T8BLB bulbs are available at Walmart for about $4.00 each. There are electronic ballasts available to fire these lamps....I had thought at one time of building an 8X10 enlarger head for my Durst 138S and stacking these bulbs as near to each other as I could.

  5. #5

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    The compact bulbs seem so easy to wire. The local Home depot stocks a medium base with a two prong plug on the back. Just screw the bulb in and attach an extension cord. I can do that much. I've no real idea how hard it is to wire a ballast. Plus the compact bulbs come in some pretty big wattages.

  6. #6

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    Quote Originally Posted by Nick Zentena
    The compact bulbs seem so easy to wire. The local Home depot stocks a medium base with a two prong plug on the back. Just screw the bulb in and attach an extension cord. I can do that much. I've no real idea how hard it is to wire a ballast. Plus the compact bulbs come in some pretty big wattages.
    Hi Nick,
    Take a look at http://www.eepjon.com/ubldit.htm. The directions are aimed building a lightsource for UV sensitive material but the general idea seems applicable here. Just pick the correct lamp for your application. As noted above light output vs watts works differently than with incandescent bulbs. Not to be silly but a good light box would provide a pre-wired solution. I have two customers who have tried this and found it to work.
    Celac.

    Standard disclaimer applies here: I have no connection with eep, just seemed like useful info.

  7. #7
    Ian Grant's Avatar
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    Nick

    Have you considered that these low enrgy bulbs take quite a while to start up and reach full ouput. I use them around my house and it's typically 10-20 seconds for decent output & a minute or so for full output.

    I started down the route of designing a 10x8 enlarger, the light source was the major area of concern, I opted for the tungsten halide lamps with built in reflectors as used in many enlargers, however an Ebay purchase made making my own redundant.

    The light box on my DeVere 5108 still gives even light output when bulbs go down, you should investigate how these light boxes work, looking at it I reckon extremely easy to make your own version, larger or smaller as well.

  8. #8

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    The camera I intend to use came with a packard shutter installed. I intend to turn the lights on and leave them on. It'll deal with warm up and should help with bulb life.

    pelerin is that basically a build your own fixture? I'm going to look carefully at the wiring.

  9. #9

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    [QUOTE=Ian Grant]Nick
    Have you considered that these low enrgy bulbs
    take quite a while to start...
    QUOTE]

    I'm going way back for this one; the late 50s. The government
    surplus F. tube 4 x 5 I bought must have been at least a few years
    old when I got it. Five, IIRC, small diameter tubes and no warm-up,
    no shutter. There are tubes and then there are tubes. How about
    the 1/8 inch tubes? Up to a foot long. Dan

  10. #10

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    Maybe I'm missing something here, but why not just buy a cold light head from Aristo and be done with it?
    My Verito page

    Anyone can appreciate a fine print. But it takes a real photographer to appreciate a fine negative.

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