Compact fluorescent enlarger head?

Discussion in 'Darkroom Equipment' started by Nick Zentena, Apr 17, 2005.

  1. Nick Zentena

    Nick Zentena Member

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    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. jmdavis

    jmdavis Member

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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. Nick Zentena

    Nick Zentena Member

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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. Donald Miller

    Donald Miller Member

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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. Nick Zentena

    Nick Zentena Member

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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. pelerin

    pelerin Member

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    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. Ian Grant

    Ian Grant Subscriber

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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. Nick Zentena

    Nick Zentena Member

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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. dancqu

    dancqu Member

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  10. wfwhitaker

    wfwhitaker Member

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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?
     
  11. Nick Zentena

    Nick Zentena Member

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    The Aristo 810 is $500+ and uses a $200 replacement bulb. OTOH if I can swing using the compact bulbs I think around $75 will pay for everything. Certainly less then $100.

    I've spent the day looking at T-5 and T-8 bulbs. Between the cost and hassle of ballasts I think I'm going to try the compacts. They're on sale now so they don't actually cost much if any more then T-8 bulbs without a ballast and fixture.
     
  12. jmdavis

    jmdavis Member

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    Nick,

    When you have your Franken-Enlarger built, you need to show us some pics. The packard is what I was thinking that you would use, but you might have had a lens in a shutter already. You'll probably want a foot switch and need an electric packard.

    I think that this type of system would seem to lend itself well to metronome timing. I really wish that my darkroom was big enough to consider something like this. But at 5x7 feet, there's no way. Oh well, maybe the next house.

    Mike
     
  13. Jon Shiu

    Jon Shiu Subscriber

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    Hi, don't know if you saw it, but I have an Aristo 810 for sale in the classifieds section if you would like to make an offer.

    Jon
     
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  15. Nick Zentena

    Nick Zentena Member

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    I was sort of talked out of the 810 a few weeks ago. Partly the cost of the replacement bulb. Partly I'll have to adapt it to fit the camera. IIRC it's also kind of heavy.

    JmDavis I'm going to fix a couple of tripod mounts to a table. If I remove the light source the camera could be unscrewed from the mounts and stored. It'll actually not be that big. My goal is 16x20 prints so all I need is 2x from an 8x10.
     
  16. inthedark

    inthedark Member

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    Nick, I use flourescent deck 20 x 24 with u-bent lights and an acrylic or polycarbon difusser. It works great. I have 6-50w50k and have simply installed holes in the perimeter then draped over an airy metal skeleton and a computer fan. However you will find many problems I think with the compact flourescent. The main one being that they do not boot up consistently and the lumens will fluctuate as the gas gets warmer. Just plug one into a timer then time them to full brightness. They seem to fluctuate as much as 5-6 seconds. My system uses a flashing ballast with regular flourescent so they are always pre-warmed will the camera is on and the timer boots it up to full brightness.

    Secondly, the concerns you have over the position of the lights isn't as important with reg flouros. . .uhm unless your prints take over 15 minutes the lights are not going to be "maintaining" the kind of heat that will cause damage to regular flourescents, with the ballast being separate you can locate it outside the light deck as mine are which dramatically reduces the heat build up on both lights and ballast.

    Well I have been perfecting using flourescent lights for color now for four years with the help of the company that manufactures my cameras and have been perfecting non-color use of them for 35 years. Hopefully this will help you make a wise decision.

    BTW, if you can't find flashing ballasts and you know anything about electronics, you may be able to use a delayed electric relay to preboot you lights.
     
  17. inthedark

    inthedark Member

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    *pre-warmed WHILE the camera . . .
     
  18. Nick Zentena

    Nick Zentena Member

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    I think I've decided on this bulb:

    http://www.1000bulbs.com/product.php?product=9185

    I'm going to deal with warm up by just leaving it on and using a shutter on the front of the camera. I wish the bulb company would provide the colour output graph for the bulb but I think the 5000K bulb should be okay for VC paper. I was intially thinking about the compact floods. The floods would have needed to be placed on thier sides. With the bulb in the link I can just place it in a normal position. The flood I used for a test with the 4x5 camera worked great. Hopefully the normal non flood bulb will work okay.
     
  19. Loose Gravel

    Loose Gravel Member

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    Remember that your light output will vary with bulb temperature and age. Small variations in light output can affect highlights that are near threshold values. This is why most coldlight users use a closed-loop controller of some kind. If you have multiple lamps, this is a more difficult problem. You are counting on the diffusion material to be quite good and I think we would all be surprised at how poor diffusion materials are.

    Leaving the lights on all the time may be a problem. Could get hot. Will reduce lamp life. Will reduce ballast life. At some temperature, lamp output will peak and then decrease as the temperature increases. Aristo coldlights have a heater, thermo, to help stabalize temperature and light output. This helps, but there is still drift.

    Good luck.
     
  20. inthedark

    inthedark Member

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    Nick, I am agreeing w/ LooseG. Not only will the luminosity vary dramatically after it gets warms with warmer = dimmer, but also if you do any color you will find that the green amps up quickly as it gets warms to 150 degrees or higher ( I mean green light effect = magenta printing effect).

    You are right that 5000K are best for VC or any other. The reason is because it is the most stable compared to Warm White, Cool White, 3200K, 4100K, and 2900K; all of which I have tested. Whatever advantages they may have initially for color work anyway, is lost within a week of use because they become unstable that fast.
    By stable I am referring to both long term life as well as the warm - hot while in use issue.
    Furthermore, with the compact flourescents I use in the house, I have found that any kind of regular on and off seems to make a seven year light last about seven weeks. Seems invariably one of the twisted up tubes goes dark, if not both.
     
  21. inthedark

    inthedark Member

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    Loose, I also agree with the general remark about diffusers, except in my case wherein my lights are a good 5" from the negative vacuum back and the lights are long tubes set side by side very close. I have even tested removing the diffuser and no difference is noticed in the even coverage in the final prints.
     
  22. Nick Zentena

    Nick Zentena Member

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    I asked on the sci.engr.lighting newsgroup and the claim was that the bulbs are rated for 25C. The basement is lucky to hit 20C. I'm going to use two 12v fans. One pushing in air one pulling it out. Yesterday I found out somebody opened up a surplus store nearby. No more 40 minute drives :D just to wander around and look at junk :smile: They have a 12v lead acid rechargable on sale this week for $12 that I'll use for the fans. Over kill but I already have the charger.

    Right now I'm thinking one of those 105watt bulbs should be enough. No? I might go for two. The intended size for the head is 12"x12"x18". With the head being at least 12"x12" I'm hoping the light will be even enough in the centre 8x10 area.
     
  23. Donald Miller

    Donald Miller Member

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    I have a 250 watt lamp in my Durst 138S which is a condensor enlarger. Due to the fact that it is a condensor enlarger it does not suffer from the light loss that diffusion material would cause. It is interesting that Durst Pro USA now offers a lamp upgrade for my enlarger that involves a 1200 watt lamp. Both of these involve far more light then you are wanting to use. My exposures can become lengthy with dense negatives using the lamp that I now use.

    I really think that considering the coverage that you are wanting to achieve that two very distinct potential problems exist. The first is the amount of light that you are wanting to use and the second is the matter of even light output over the negative area. Thus I would say that your concern about heat output may very well be the least of your concerns.

    However, it is when people learn to think outside the box of conventional practice that oftentimes new methods are discovered. There is also the concept of one being "penny wise and pound foolish".
     
  24. Nick Zentena

    Nick Zentena Member

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    Donald that 250 watt bulb isn't a fluorescent is it? I'm also guessing the Durst is capable of making bigger enlargements. I'm building everything so it'll be big enough for 3x from 8x10 but the goal is 2x. I could easily add more then one bulb to the head. All it'll take is drilling a hole for each bulb.

    About two weeks ago I did a test. Old 4x5 monorail. 19 watt fluorescent flood light. The projected image was quite bright. I didn't try to make a print but did take an incident meter reading. It was better then I expected. The 105 watt bulb is allegedly equal to a 500 watt incandescent. I'm also counting on the 5000k bulb being a better match to photo paper then a 2700K bulb would be.
     
  25. phfitz

    phfitz Member

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  26. Donald Qualls

    Donald Qualls Member

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    Did you read that page? Those things (stripwise electroluminescent panels, I think) cost $75 and run off a 9V battery -- which means they can't output as much light as a pocket flashlight. Similar units in useful power levels would be very welcome, but at that pricing, it would cost much more to build an enlarger light source with them than it would to simply buy a color head with high power hot light -- and then install a cooling system for it to keep your darkroom comfy!