Got a new printer, may need rewiring

Discussion in 'Contact Printing' started by kb244, Jan 24, 2008.

  1. kb244

    kb244 Member

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    So as we're packing up the store (yes the "Camera Center" I work in is finally closing it's doors, tho will try to stay online), I came across one of the items buried in the basement and decided to buy it primarily cuz of the aesthetics (it'll be prettier when I clean most the dust off the outside) but would also allow me a compact lil unit to do some 4x5 contact printing when I didn't want to have to worry about a light source to place off a typical contact frame.

    In any case I replaced the two 100W household bulbs with two 27W (equiv to 100W) daylight balanced florescent bulbs. Then I goto plug it in... oddly enough the switch is a direct on/off type of switch, well when I turn it on one of the bulbs lights up, if I turn it off then back on the other might turn on or the first one will light up again. Looking again I noticed that whatever bulb didn't come on looks like it's trying to come on, as if the path of wiring has not allowed the second bulb enough "juice" so to speak.

    issue 1 - wiring

    Now I'm assuming though since its all Alternating current that it should be fine in parrallel with each other. Right now its going from the wall... connects to the red bulb, which also connects a wire to one of the white bulbs on the same contact. from the one white bulb, it goes to another white bulb, then that one white bulb goes to the rocker switch, then from the rocker switch goes to the other contact on the red bulb area. The red bulb then connects into a push switch which then leads back out to the AC current.

    So basically push button turns on/off the whole unit which is connected thru the red bulb, and the white bulbs piggy back off the contacts on the red bulb being interrupted by a rocker switch.

    Now by design I think making one bulb follow the last is probably not the best way to do it, and that instead I should perhaps make a common lead to all the bulbs on one end, but then run then one after the other on the other line. (ie: they all directly connect to 1 wire, but run one after the other on the other wire). So basically looking for confirmation on rewiring.

    issue 2 - diffusion

    Right now the lid has a small 5x7 cut of frosted glass separated by about an inch from a sheet of clear glass. what I want to do is put four pegs in the corner down near the bulbs and drop in a larger peice of frosted glass in hoping of diffusing the light even further before hitting the negative. Also because I'm using lower wattage (27W each) bulbs and duration is not constant I could also maybe use a solid white lenoleum or some other kind of plastic/polymer block, kinda like what you see on those cold heads on enlargers.

    Advice on this?

    Pictures

    [​IMG]

    [​IMG]
     
  2. Jon King

    Jon King Member

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    If I understand your description, the two white bulbs were wired in series, so each gets half of the voltage. Incandescent bulbs would be dimmer, but perhaps they got a better light distribution that way. It looks like the ballasts in the base of the CFL's won't run on half of the intended voltage.

    I agree, I'd rewire the white bulbs so they are in parallel.

    (and perhaps splurge on a new cord and plug!)
     
  3. CBG

    CBG Member

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    The output from CFLs is said to be unpredictable as they start up. You may find it difficult to get consistent exposures if that is true. It would be interesting if you followed up later to say how well the CFLs work in a contact printer.

    Best,

    C
     
  4. BobNewYork

    BobNewYork Member

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    I do know that the CFs I used in my house to replace my incandescent bulbs and stop global warming dead in its tracks take a while, quite a while actually, to come to full power. If the warm up time is consistent I guess you could "account" for it in your printing times. Can't help with the wiring I'm afraid - I'm clueless. But I do have to say that's a really cool looking piece of equipment!
     
  5. DWThomas

    DWThomas Subscriber

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    Agreed that it sounds like the two are in series which is likely to come to grief with CFLs.

    The picture brings back memories, as my father built something very similar to that circa 1948 or so. I believe it was from plans in Popular Mechanics or one of those legendary magazines of the era.

    DaveT
     
  6. kb244

    kb244 Member

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    By the way what does CFL Mean....

    Also I assume #1 in the illustration I drew is what is meant by Parrallel, #2 is how the bulbs are currently wired.

    [​IMG]
     
  7. DWThomas

    DWThomas Subscriber

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    CFL = Compact Fluorescent Lamp

    Yes, #1 is parallel and probably the way to go.

    DaveT - Apologizing for the TLA (Three Letter Acronym)
     
  8. kb244

    kb244 Member

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    Also given the possible age of when the contact printer was put together, I'm assuming that two 100W bulbs was bright enough to make an impression on contact printing paper in a couple of seconds, where as paper now days is 10x more sensitive than contact printing paper.

    Also my co-worker said the other benefit of putting a second sheet of frosted glass inside the box in the middle, aside from diffusing the light source even more, is that I can drop lil peices of paper or 'cookies' and such on the frosted glass to kind of 'dodge' parts of an image as the diffusion will soften the edge as the light travels and I can preview the negative with the lights on doing something like that (hell worth a try, and the method I'm gona use to float the glass I can easily remove the sheet if necessary without disassembly)
     
  9. richard ide

    richard ide Member

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    Karl,
    I would forget about CFL's and get a couple of 7.5w or 15w bulbs. try in series but even then the light might be too bright and you might have to use something to diffuse the light even more. When I was doing production printing I was using a 100w bulb reduced to about 20w but at about 5 ft. distance.
     
  10. copake_ham

    copake_ham Inactive

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    Blaming CFLs is a red herring. Whether or not you use CFL's or incadescents - it seems there is a wiring problem.

    Which type of bulb is in the socket is immaterial once the CFLs warm to full light.

    I would first check the efficacy of your switch and also replace the main plug and wire. To begin with, they look like fire hazards.

    There's a reason that thing was stuck into the basement to begin with - and it was problem long ago - certainly long before there were CFLs.
     
  11. PHOTOTONE

    PHOTOTONE Member

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    There is not a wiring problem if you use the tungsten bulbs originally intended for this printer. They were wired in series to cut down their output, and to ensure the printer did not light up if one bulb was burned out. If you must use the compact flourescent bulbs, you wil have to rewire in parallel, and your wiring diagram shows both wires shorted out at the switch. In truth, only one side of the electric service needs to go thru the switch. So, to verbalize it. One unswitched lead from 110v service needs to go to one terminal on each socket. Another lead (from the switched side of the 110v service) needs to go to the other terminal on each socket. You may find that with the CFL bulbs your exposure times are too short for modern enlarging paper.
     
  12. JBrunner

    JBrunner Moderator Staff Member Moderator

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    I wouldn't blame CFL's for anything, but they are the wrong thing for this tool.

    I would say they are unlikely to work in a satifactory way in this type of printer. The exposures will be far to short for the CFL type bulb to even out into any type of consistency, even warmed up, because they are many many times too bright for modern paper, in this type of printer. (Unless you have a AZO stash, and you'd be nuts to wreck a bunch of AZO tying to make the CFL's work.) My "experiments" with CFL's in a diffusion enlarger also indicate uneven spectral distribution that mimics the spiral of the bulb, a sort of spectral phasing that casts alternating green and magenta spirals, so contrast will be all over the place on the same print with VC papers, even if you could get them on and off in a consistent predictable way, if your experience turns out like mine. The proximity of the bulbs to the diffuser in the contact box will likely exacerbate that problem. I found that I could get the CFL to come on in an "sort of" predicable manner if I pre-burned them for a few minutes, and struck the lamp within about thirty seconds. Not much time to get paper in and adjusted, and if you don't make it, you get to put the paper back and start over. (except these bulbs are gonna fry your paper anyway, unless your negatives look like a welders mask)

    Not worth the PIA,even in an enlarger, where the output power was at least in a useful range.

    Find 7.5w tungstens, and double diffuse, as suggested, or look into LED. The small output of an LED might be ideal in this application, and since you can get them in edison base, and you can get them in colors, and your going to rewire it, you could have two switches, one for green, and one for blue, and have a ready made split printer.

    That's what I'd do. (Unless I'd been drinking)
     
    Last edited by a moderator: Jan 25, 2008
  13. JBrunner

    JBrunner Moderator Staff Member Moderator

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    There isn't a wiring problem, it was made to run half voltage to two incandecent lamps.

    The bulb type isn't immatierial for photographic printing. There are many factors at work, including spectrum. See my post above.The idea that this type of bulb can be a direct replacement in all applications is the red herring.
     
  14. kb244

    kb244 Member

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    You do have a point on both counts, and remembering how Florescents work that does raise a concern for short-period exposure on photographic paper.

    I'll likely go the route you mentioned lower wattage conventional bulbs (like 25 or so that they'd go half at 12 or so) Course if I go LED I'll redo the wiring completely and put those lights directly on the bottom of the box facing up but either route would work for the additional diffusing panel I was taking about because I want to experiment with the idea my co-worker came up with in terms of dodging contact prints by laying shapes down on the lower diffusion board.
     
  15. PHOTOTONE

    PHOTOTONE Member

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    That is no experiment, it is a proven technique for contact prints made on a contact printer.

    There was at one time (newer than your machine) a super-deluxe volume production contact printer that had a whole bank of small lights, each one with its separate on-off switch, the idea being that you could adjust the exposure across the LF negative to give dodging and burning effects. Say you needed more exposure in the sky, you would leave those lights on full, and say, possibly switch off every other light on the rest of the negative area. Of course the whole light source of many small bulbs was diffused thru an opal glass, upon which you could also lay dodging papers, as this was below the glass plate you put the negative on. Quite a machine.
     
  16. kb244

    kb244 Member

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    :tongue: Technically its an experiment for me if I am making sure I actually do it right :D
     
  17. BobNewYork

    BobNewYork Member

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    I believe that Stouffer Technologies in South Bend, Indiana still makes these contact printers.
     
  18. kb244

    kb244 Member

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    :tongue: Probably for more than I want to spend too :D But actually nice to know they're available new.
     
  19. ic-racer

    ic-racer Member

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    Another way to make it more even is to get the diffuser closer to the negative. The less the center of the negative can 'see' of the edges of the diffuser, the better.

    BTW there is a very cool 'doging' contact printer on e-bay. (item no. 150215888469) It has been listed for quite a few months but I couldn't get the guy to come down from $650. I thought this would be a great project to make the ultimate VC contact printer but wound up getting an 8x10 enlarger instead.