Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,840   Posts: 1,582,509   Online: 952
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 20

Thread: Safelight Bulbs

  1. #1
    geauxpez's Avatar
    Join Date
    Jul 2006
    Location
    Atlanta
    Shooter
    Multi Format
    Posts
    107

    Safelight Bulbs

    I recently was given a nearly complete darkroom setup by a friend that included a "Yankee Safelight SL-2". On the label, it says "110 volt 15 watt". The bulb that was in it was a Sylvania NO. 140 75w-120v and it seems to get awfully hot awfully quickly. I bought a compact florescent 19w 120v bulb (supposedly equivalent to a 75 watt incandescent bulb) to replace it (and hopefully run cooler). Any ideas or suggestions?

    Thanks,

    Adam

  2. #2

    Join Date
    Oct 2005
    Location
    Calgary AB Canada
    Shooter
    4x5 Format
    Posts
    235
    Images
    8
    Do not use a 75 watt lamp in a 19 Watt enclosure. It is a definate fire hazard.

    Do not use a fluorescent lamp in a dark room. They glow in the dark, which can fog your film.

    Buy the proper lamp. The 75 watt lamp will fog your paper.

  3. #3

    Join Date
    Dec 2004
    Shooter
    Multi Format
    Posts
    1,670
    Even though a fluorescent bulb may be rated at only a fraction of the wattage of the bulb it replaces and the incandescent bulb happily worked in a confined space, I have found that being in the confined space severely limits the life of the fluorescent bulb. Evidently the electronics in the base needs plenty of air circulation.

  4. #4
    raucousimages's Avatar
    Join Date
    May 2003
    Location
    Salt Lake
    Shooter
    Large Format
    Posts
    825
    Just us ea 15W bulb, problem solved. If you can't find one at a hardware store try a lighting store, they will have them.
    DIGITAL IS FOR THOSE AFRAID OF THE DARK.

  5. #5

    Join Date
    Nov 2004
    Location
    Italia
    Shooter
    Multi Format
    Posts
    4,680
    Isn't 15 watts just an appliance bulb?

  6. #6

    Join Date
    May 2005
    Location
    Woonsocket, RI USA
    Shooter
    35mm
    Posts
    2,725
    You could also ditch the safelight filter and substitute a red or amber LED bulb. I've not tried this approach, but there have been some threads here on LED safelighting recently, and it seems like a reasonable and energy-efficient way to go (not that a single 15W incandescent bulb is a huge energy hog, but every little bit helps).

    As to fogging and wattage, most safelights use low-wattage bulbs and include instructions to keep them at least a certain distance from the paper (usually about 3-4 feet, IIRC). It's conceivable that a 75W bulb would be OK if kept much further away than that; you'd need to do some tests to be sure. Similar comments apply to using a 19W fluorescent bulb -- fluorescents put out more lumens per watt than do incandescent bulbs. I wouldn't worry about fluorescents fogging B&W paper if the fluorescent is used in a safelight with a proper filter; after all, the point of the filter and light-tight enclosure is to prevent light getting out except for light that's safe to the paper. Fluorescents fogging paper is an effect of the bulb continuing to glow when the light is turned off. This is an issue for normal room lighting, but in a safelight it's a non-issue, unless perhaps you turn on the safelight and then turn it off to handle film or color paper.

  7. #7
    Monophoto's Avatar
    Join Date
    Aug 2004
    Location
    Saratoga Springs, NY
    Shooter
    Multi Format
    Posts
    1,691
    Images
    44
    Adam -

    The 15W rating implies two things:
    1. The light output (measured in lumens) is less than that of a 15W incandescent lamp. Using a bulb that is any brighter than that has the potential of causing fogging.
    2. The electrical design of the fixture assumes that the power consumption of the bulb will be 15W or less, and using an incandescent bulb that consumes more could cause overheating and possible fire.

    Substituting a standard off-the-shelf-at Home-Depot CFL for an incandescent bulb may get around the second limitation, but the light output of a CFL will be greater than the light output of an incandescent bulb of the same rating. So you will still have the first problem - potential fogging. If you do some shopping on-line, you can probably find CFLs with much lower lumen output ratings that you could use if you prefer that kind of light source.

    There are two situations that favor using CFLs -
    1. Energy consumption per lumen of light output is much higher than with incandescent bulbs. This is significant in instances in which the light will be on for extended periods.
    2. The life expectancy of a CFL is considerably longer than with incandescent bulbs. This is significant when replacing bulbs is either inconvenient or has an unacceptable cost - for example, in commercial applications where they have to pay someone to screw in new bulbs, or on those fixtures at home that require that you get on a tall ladder to replace the bulb.

    In my opinion, a darkroom safelight doesn't fit either case, so I suggest sticking with an inexpensive appliance bulb.
    Louie

  8. #8
    geauxpez's Avatar
    Join Date
    Jul 2006
    Location
    Atlanta
    Shooter
    Multi Format
    Posts
    107
    Thanks guys. I am now wondering if that 75w bulb was actually a spare enlarger lamp bulb placed in the safelight to keep it from getting broken. Who knows. I'm glad I didn't actually use the 75 (or the CFL for that matter). I'm still in the "getting it all together" stage.

    Thanks again for the replies & explanations.

  9. #9

    Join Date
    Oct 2005
    Location
    Calgary AB Canada
    Shooter
    4x5 Format
    Posts
    235
    Images
    8
    A flourescent lamp will fog panchromatic materials such as Tri-X film. They glow in the dark after the power is off. They can even absorb photons from the other lamps in the darkroom and glow. Kind off like the luminous dial on a Gra-lab timer.

  10. #10
    raucousimages's Avatar
    Join Date
    May 2003
    Location
    Salt Lake
    Shooter
    Large Format
    Posts
    825
    We (Lowes) sold appliance bulbs in 15, 25, 40 and 50 watt if I remember right but seemed to always be out of 15.
    DIGITAL IS FOR THOSE AFRAID OF THE DARK.

Page 1 of 2 12 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin