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Carl Weese
16-Aug-2004, 08:51
Does anyone know a source of blue lightbulbs in *low* wattage? I don't want powerful "photoflood" bulbs with a blue coating, just regular low residential wattage (60 watts or so) bulbs with higher than normal tungsten color temperature. This is for 4x5 chrome work where light will be mainly windows and pack&head strobes but numerous regular lamps form part of the decor and I want the lamps to be illuminated without going deep amber. I guess the other alternate is to make sleeves of Roscoe acetate filters and slip them over existing bulbs.

David A. Goldfarb
16-Aug-2004, 09:04
If they fit the fixtures, another alternative might be screw-in AC slaves like this one:

http://www.bhphotovideo.com/bnh/controller/home?O=NavBar&A=getItemDetail&Q=&sku=89949&is=REG&si=acc#goto_itemInfo

I'm guessing the window must be in the photograph or multiple exposure with filtration for the tungsten would be another option.

David Karp
16-Aug-2004, 09:12
Carl,

GE makes medium base light bulbs under the brand "Reveal" with higher than normal color temperature. I could not find the Kelvin rating on the bulb, but they are much cooler than a standard light bulb.

I hope this helps.

jnantz
16-Aug-2004, 09:36
try gray supply company. they have pretty much every bulb made, at a deep-discount. even stobe and lowel ( tungst. ) bulbs. http://www.topbulb.com

John Cook
16-Aug-2004, 10:47
If you can find a rental house with some old stuff, you might be able to rent a Colortran unit.

They were very popular thirty or forty years ago. We had several in the studio for years. Basically a transformer about the size of a car battery, having a rotating switch for various levels of output voltage.

The idea was that regular household bulbs could be used instead of expensive photofloods. As you know, photo bulbs are manufactured to run on 60 or 80 volts. When you plug them into normal 110 volts they burn brighter and bluer.

The same effect was achieved with the Colortran unit. Normal bulbs were burned at 110 volts as modelling lamps. When the final exposure was made, the Colortran unit was cranked up to 120, 130 or perhaps 140 volts to get the proper Kelvin temperature for Type B color film. As soon as the exposure was made the unit was turned back down to extend the life of the bulbs.

I suppose if you can’t find an old unit, something like this could be made up fairy cheaply.

Just another historical tale from the Old Duffer...

Ted Harris
16-Aug-2004, 12:41
As another old duffr responding ..... Colortran units (and othr similar) are actually still manufactured. Meanwhile, you can find them very reasonably on eBay all the time.



Another answer iw to make 'shades' out of #10 cans and gel the end of the can with the right rosco gel.

Carl Weese
16-Aug-2004, 14:44
Dave, thanks for the "Reveal" brand lead. I'll look for it and get color temperature readings.

The Colortran is interesting but sounds like it would increase light intensity, which I don't want, and might not work for trying to change the color of four or five different fancy little lamps scattered around a fancy country Inn suite of rooms.

Maybe "wraps" of 1/2 CT Rosco filter material will be the answer, but relamping seems simpler if I can find the bulbs.

lee\c
16-Aug-2004, 19:45
I bought some 100 watt bulbs that are blue from Home Depot about a month ago. Can't remember the name but they are available.

leec

ronald moravec
17-Aug-2004, 05:06
Block window light and shoot the interior with a conversion filter, the turn the lights off, unblock the windows, and make the outside exposure.

Or visversa and start with tungsten film and shoot the outside with a conversion filter and second exposure.

Or cover the window with conversion film and shoot with tungsten film all at one time.

Night day sequences also work.

Martin Courtenay-Blake
17-Aug-2004, 08:43
Try artists suppliers. They usually keep 60 and 100 watt versions. They are usually refered to as "daylight" bulbs and are used by painters to reproduce natural daylight for painting in the darker months. Unlike blue coloured bulbs these are colour matched to about 6000 degrees K.

These are also the best way to view colour prints if a good northlight is not available i.e. in the darkroom or at night.

Martin

Donald Brewster
18-Aug-2004, 10:23
I'm partial to the Chromalux bulbs. Made in Finland and used by lots of art galleries and museums. The GE Reveal bulbs are good, but they are not quite "daylight" or "full spectrum", but they are cheaper and more readily available than the Chromalux bulbs. Here is an interesting article from RPI in New York on some of the characteristics of various "full spectrum" lighting products: http://www.lrc.rpi.edu/programs/nlpip/lightingAnswers/fullSpectrum/lightSources.asp

Carl Weese
18-Aug-2004, 11:26
The GE "Reveal" turns out way off the mark. A 60 watt metered 100 degrees Kelvin warmer than a standard 60 watt bulb, with a strong green tint that would need 20M filtration to fix. 100 degrees is a quibble, but any movement to green is completely counter-productive. (Measured with a Minolta colormeter than measures both red/blue and magenta/green color axis.)