Continuous Lighting, Daylight Color Temperature

Discussion in 'Lighting' started by RonJ, Mar 24, 2006.

  1. RonJ

    RonJ Member

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    I've been playing with my new light tent using a large window to supply sunlight. This is very limiting as to when I can shoot. Is there anysuch thing as continuous lighting that has a color temperature approximating daylight? I prefer not to use filters on my lens, but I wouldn't be averse to filtering the lights. Any suggestions?
     
  2. Dave Parker

    Dave Parker Inactive

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    There are quite a few companies out there that make daylight balanced bulbs for studio use, you can buy bulbs of virtually any color temp you need..

    Dave
     
  3. AZLF

    AZLF Member

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    I have purchased daylight rated photo bulbs in 500 and 250 watt ratings.They are available in most well stocked camera stores. I know you can get quartz lights rated at daylight level. A commercial photographer I worked with used nothing else in the studio for product shots with the exception of food photos. At times we would have a several thousand watts of quartz going for large items or desired lighting effects.
     
  4. Helen B

    Helen B Member

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    As already mentioned, there are daylight lamps out there, particularly fluorescents. Daylight balanced florries with a high CRI (colour rendering index) might be your best option.

    Incandescent lamps lose about two stops when filtered to daylight with a gel (a full CTB) so it is quite common to filter the windows instead (full CTO or CTS depending on your preference). That makes it much easier to get the balance between the daylight and the artifical light. If you used tungsten film you wouldn't need a filter on your lens.
    As you are using the window as a source of light you don't have to be as careful filtering it as you would have to be if the window was in shot.

    If you want to use incandescent lamps filtered to daylight, dichroic filters would be better than gel ones because they lose less light and they last longer, but they are more expensive.

    Best,
    Helen
     
  5. eric

    eric Member

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    You need to get something from 5000k-5500K color temperature lights. I just got some 5500K Flourescents and they work great for what I'm doing. Same with hotlights but they are umm. hotter! :smile:
     
  6. RonJ

    RonJ Member

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    Gee, I didn't expect so many replies so quickly! I'm new to this site and didn't know what to expect. Thanks everyone.
     
  7. David H. Bebbington

    David H. Bebbington Inactive

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    I am doing a project where I photograph flowers in the studio with narrow depth of field. As I could not switch my 600-joule flash heads down far enough for an aperture of f2.8 and photofloods would be far too hot for flowers, I got two daylight bulbs which are rated at 6400 Kelvin, consume 45W and are supposed to emit as much light as regular 225W bulbs. Having reminded myself what a mired is, I did some calculations and figure that an 81A filter will give correct color rendering (possibly an 81B or 81C might look more pleasing). I have just shot some tests and am awaiting the results. The fluorescent lamps are pleasant to work with, they're even cooler than the modeling lights on my flash.

    Regards,

    David
     
  8. Nick Zentena

    Nick Zentena Member

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    B&W has or at least had a document on filters. In the back of it is a little diagram for figure out temperture filters.
     
  9. JBrunner

    JBrunner Moderator Staff Member Moderator

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    Since you've got the big daylight source, you might enjoy some color temp mixing, something like using T64 and lighting the subject's front with tungsten light, and letting the rim and background be blue. Its a little tricky at first, but you can learn how to manage some great effects.
     
  10. Drew B.

    Drew B. Subscriber

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    Or you can just use NPS film to solve your problems.
     
  11. Helen B

    Helen B Member

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    An 81B (+27 mireds or reciprocal megakelvins, MKˉ¹) certainly seems about right to change a CCT of 6400 kelvins to 5500 kelvins. A KR3 (+ 30 MKˉ¹) would also be close. Are you using reversal film or neg film?

    Best,
    Helen
     
  12. Lee L

    Lee L Member

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