Flourescent lamps

Discussion in 'Darkroom Equipment' started by Adrian Twiss, Sep 10, 2010.

  1. Adrian Twiss

    Adrian Twiss Member

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    My darkroom is 10ft by 10ft by 7ft and is lit by 3 large spotlights. The biggest problem is that they put out a lot of heat and also the quality of light is not that good.

    I intend to replace them with 6ft 70 watt fluorescent tubes in a twin light fitting. I was going to opt for daylight tubes with a colour temperature of 6500K. A prismatic diffuser will help bounce the light around a bit. Hopefully they will run a bit cooler as well.

    My main concern is afterglow. My electrician says that tubes have improved over the years and afterglow is no longer a problem.

    Is there anyone out there who has fluorescent tubes fitted in their darkroom and did you have any issues with them?

    Thank you.

    Adrian Twiss
     
  2. mike c

    mike c Subscriber

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    I had a set of 4' don't know the wattage but they did glow after I turned them off.Checked for after glow by letting my eye's adjusted to total dark then turned on florescent for a minute while shielding my eye's ,turned off light and open my eye's and there was the glow.There were very old bulbs so do not know how if newer ones glow or not.
     
  3. ajmiller

    ajmiller Subscriber

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    We had them in our college darkroom and they were wrapped in safelight (red) gel I seem to remember.

    - Tony
     
  4. Neal

    Neal Subscriber

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    Dear Adrian,

    I took out two 8 foot fixtures from my garage 2 years ago because getting the bulbs back and forth (purchase and recycle) became more of a chore than I liked. The bulbs did clearly glow a bit after turning them off, but I don't know if it would have caused a problem. I use CFLs at the moment and have moved my printing into the garage due to some remodeling. No problems noticed but they are a good distance from the printing area. I also worked in a public darkroom that had U-shaped fluorescent fixtures for about a year. Again, the fixtures were a good 10 feet away from the printing area but they caused no noticeable fogging.

    Good luck,

    Neal Wydra
     
  5. Steve Smith

    Steve Smith Subscriber

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    I had a tube in the darkroom at my last house. I don't recall it causing any problems.


    Steve.
     
  6. Tom Kershaw

    Tom Kershaw Subscriber

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    I use halogen lighting in my darkroom which switches on and off with very minimal afterglow. I'd be concerned about frequent on-off cycling of the fluorescent tubes (Steve Smith may be better qualified to comment here), which in my experience do tend to show an afterglow.

    Tom
     
    Last edited by a moderator: Sep 10, 2010
  7. climbabout

    climbabout Member

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    Adrian - I have worked in the electrical supply business for close to 35 years and while the ballast and lamp technologies of fluorescent lights have changed over the years, the lamps still emit an afterglow. Even the newer compact fluorescent spiral lamps. I tried some of these recently and have switched back to standard halogen and incandescent. The glow is not noticeable under normal lighting conditions, but you can certainly see it in a darkened room - especially once your eyes have adjusted. The afterglow is not likely to be bright enough to affect photographic paper, but it would probably affect film - to what degree I'm not sure, but why take the chance?
    p.s. - If you absolutely need to use the fluorescents for general illumination - just put another smaller light in the room to use just before you need to handle film and leave the fluorescents off. Thats what I used to do. If the fluorescents have been off for several minutes (10 or 15), the afterglow will be gone.
     
  8. michaelbsc

    michaelbsc Member

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    I too have noticed the afterglow in the lamps. Frankly, thinking about how the coating fluorescences I cannot think of a way they could be manufactured that would not afterglow.

    Hold out for LEDs if the heat is unbearable. It is more expensive, but the operating costs are lower to help offset the expense.
     
  9. Dave Martiny

    Dave Martiny Member

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    I once bought a desk lamp that used a circular flourescent tube with a large magnifying glass in the middle, thinking this would be great for examining negatives and contact prints in the darkroom. The afterglow was outrageous. However, I have typical 4' flourescent ceiling fixtures in my darkroom that to my eyes show no afterglow at all.

    Regards,

    Dave
     
  10. Casey Kidwell

    Casey Kidwell Member

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    Adrian, I'm just curious why you have so much illumination in your darkroom. Are you judging test strips and you want more even light for it?
     
  11. jeffreyg

    jeffreyg Subscriber

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    I've had two fixtures of two each fluorescent tubes 4ft 40watt (5000K) in my darkroom for thirty-four years with no apparent problem. I also have an incandescent fixture on a separate switch as well as having each of the fluorescent fixtures on separate switches. I have two red safelights which probably "drown out" any after glow during printing. I use the incandescent light when doing pt/pd printing to avoid any uv from the fluorescent bulbs and to inspect prints during a printing session. If needbe you can get a reflector/socket with a spring clamp in a hardware store and use that when you don't need much light or to inspect prints while printing.

    http://jeffreyglasser.com/
     
  12. mike c

    mike c Subscriber

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    Got a incandescent spot light that I use to check test strips some times,but usually step out side into the day light to judge them after a quick micro wave tanning bath to be more sure.
     
  13. photomc

    photomc Member

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    There have been post about this, seems like scootermm may have had a issue (12x20 film) where the after glow caused some fogging of film while loading. Maybe he will see this and refresh my memory or you could try a search and will bet you find something
     
  14. Reinhold

    Reinhold Subscriber

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  15. Adrian Twiss

    Adrian Twiss Member

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    Firstly, thank you to all that posted. Your insights are much appreciated. My darkroom is a converted bedroom and I simply did not change the lights from the original fittings. They get so warm I leave them off whenever possible. When judging a test strip I use a 40w lamp clipped high up on one of my cupboards. I also have a 20 watt lamp in a clip on anglepoise lamp on my light box table. For colour print analysis (on the rare occasions I print in colour) I have a 100watt blue daylight lamp in another tall clip on anglepoise lamp. Nothing like keeping your options open eh?:tongue:
     
  16. Martin Aislabie

    Martin Aislabie Subscriber

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    All my domestic fluorescent lights have afterglow - both the mini/bulb type and the long standard tubes.

    I remember something on APUG a few months ago saying the UV glow lasting for up to 15 minutes

    I saw a very neat arrangement in someone’s darkroom of a cluster of small halogen bulbs arranged to illuminate the sink area to assess wet prints, the overall light level wasn’t that high but with the Halogens on the sink area was very well lit.
    There was a pull cord at the sink to switch the Halogens on and off.

    Martin
     
  17. JBrunner

    JBrunner Moderator Staff Member Moderator

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    No matter what anyone says here, because your darkroom, paper, and darkroom geography are unique to you, you will only know if you TEST. :smile:
     
  18. George Collier

    George Collier Member

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    I have three 4 footers in my darkroom which I use only for sustained work in the light. My print judging light is incandescent and mounted in the fix area, over an angled piece of plexi, the voltage finessed to allow for "drydown" - a whole nother subject, don't get us started.
    The material point is that incandescents might be better for constant on and off application.
     
  19. fschifano

    fschifano Member

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    I doesn't really work that way. The safelights may "drown out" your ability to see the afterglow, but that doesn't mean it isn't there. Granted, it may not be enough to cause a problem, but you never know. It all depends on the intensity, the distance from your work, the sensitivity of the material, and the length of the exposure - just like anything else. My darkroom is very small, only 4.5 x 9 ft., and is illuminated with a single, bare bulb, 60 watt incandescent lamp. It is the only room that uses incandescent lamps at this point. I tried using a CF lamp in its place, but noticed that the afterglow was very apparent, and decided that maybe using one there wasn't the best idea I'd had that day.
     
  20. Reinhold

    Reinhold Subscriber

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    This is a repeat of my post back in 2003 on afterglow...

    "... Just for the heck of it, I took a reading of afterglow with a Pentax digital spot meter held up against a bare 4' warm white flourescent tube and took a reading within 5 seconds of turning it off (in my darkroom, of course).

    Wanna guess what it read??? Zeeeero.

    Ok, lets assume that the light was actually E.V. 0.9, and couldn't trigger the meter to respond with a positive reading. How long would a medium speed panchromatic film have to sit on a countertop (4 feet below the light) before it would show noticeable fog?...??

    Also... afterglow diminishes with time... I can't visually see any glow after a minute or so, even with eyes that are fully dark acclimated. When I process 400 speed film or Konica 750 IR film, I wait 2 minutes before opening the wrapper. Been doing it for nigh onto 30 years now...

    I routinely latensify film in the same room (using a #3 filter in a Kodak beehive safelight) for 16 minutes, and have yet to get even a hint of uncontrolled fogging from fluorescent lights.

    Afterglow is a not a bugbear in my darkroom..."

    Reinhold

    www.classicBWphoto.com
     
  21. JBrunner

    JBrunner Moderator Staff Member Moderator

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    The afterglow of most fluorescent sources falls mostly outside of a meter's spectral sensitivity, so it isn't a surprise that the meter read nothing. Paper, however, has a broader range, and may "record' what the meter doesn't. Most likely a practically undetectable low grade fog, dinging up those sparkling highlights (less so for panchromatic film, and unexposed film might just get a tiny little kick to B+F, usually no biggie). Many a person searches for a technique that will give them that range they see in certain prints. Most of the time it isn't a technique that is at fault, rather a cruddy lighting, safelight, leak, or afterglow situation in the darkroom when printing. Even though paper is slow by comparison to a lot of film, it spends a lot more time out of the box, so the cumulative effect can be much more apparent. Again I am talking about something that borders on insidiousness. Most people notice gross problems right away. I have seen this tiny little dinge gremlin more than I care to recount, even in "perfectly fine" darkrooms that have been in use for years. (not saying there is anything wrong with yours)

    The only way to know for certain is to perform a safelight test with pre-flashed paper, the same paper you print, under your personal printing conditions. The slight pre-flash recommendation is particularly relevant in regard to weak sources of contamination. It might not show with unexposed paper. Testing is the only sure thing. Everything else is speculation.
     
    Last edited by a moderator: Sep 13, 2010
  22. Martin Aislabie

    Martin Aislabie Subscriber

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    How very true

    Martin
     
  23. RalphLambrecht

    RalphLambrecht Subscriber

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    Adrian

    Incandescent lighting is preferred over fluorescent lighting. Incandescent bulbs are designed for frequent on/off switching. They have no lengthy ramp-up and are immediately at full power, which they maintain consistently. The bulbs do not continue to glow after they are turned off, and their color temperature is similar to typical domestic and gallery lighting, making incandescent lighting more conducive to accurate image tint evaluation.

    A dedicated location for dry or wet print evaluation is an important feature of a well-designed darkroom. The area should be evenly illuminated and closely simulate final viewing conditions. Prints produced and evaluated in brightly lit darkrooms end up looking too dark in dimmer environments. A 60-100W opal tungsten bulb, a distance of 1-2 meters from the evaluation board, provides an illumination of around EV 6 at ISO 100/21°. This setup simulates rather dim display-lighting conditions and is ideal for dry print evaluation. However, don’t forget to consider print dry-down when evaluating wet prints.