American Cinematographer - August 1990 - 16

♦ ♦ ♦

Q.What is the"tungsten-halogen"
purpose and logic
lights?
*

behind

A# Conventi
incandescent
bulbs
maintainonal
proper
color tempera¬
*

ture for

only a very short period of time.
From almost the instant the bulb is turned

it very slowly begins to decrease in
both light output and color temperature.
At the high temperatures at which the
on,

tungsten filament operates, the surface
tungsten molecules "boil off" or evapo¬
rate. As a result, the filament gets thin¬
and its resistence to electric current
becomes greater. Less current flows, and
the heat generated diminishes, causing
ner

drop in color temperature and light
output. This condition is aggravated by

Lighting magic in the palm of your hand
incredibly versatile dedolight®'s magic begins with a quick change act. With
speed of light it becomes:
a mini spot - with a beam angle narrow enough to pick out and highlight the

The

the
*

smallest details
*

maxi flood

with wider coverage

than you'd think possible from

fixture

this small
* with hard
* with soft

And that's

enough edges to emulate the most sophisticated follow spots
enough edges to blend in on the most complex sets.

just the beginning.

dedolight® 's projection
turns it into a master

framing shutters,

tor, with

iris, and

accessory

pattern projec¬

over

the fact that after leaving the filament,
the tungsten molecules are deposited on
the inside surface of the glass bulb, fur¬
ther reducing light output.
With tungsten-halogen bulbs,
with conventional bulbs, the tungsten
molecules begin to evaporate from the
filament at operating temperatures. But
the tungsten-halogen bulb is filled with
as

halogen gas, such as chlorine, iodine,
bromine, etc. As the molecules evapo¬
rate, they combine with the halogen gas,
and are thus prevented from being de¬
posited onto the glass envelope. The gas
subsequently deposits the molecules
a

back onto the filament and the

cycle is
repeated. Voila! The filament does not
get thinner and the output and color tem¬
perature remain constant for the life of

300 available gobo

patterns.

the bulb.
Further information can be
found in Anton Wilson's "Cinema Work¬

shop."

The

focusing

range

The incredible

grand finale? A demonstration of
dedolight®'s incomparable 25:1 spot-to-flood
and 350 watt fresnel punch, all from a 100 watt fixture.

dedolight®. Let its magic bring magic to

your next

location.

International Agents:
CD Leman, Vienna © 01-859 7650 © Lemac, Melbourne © 03-429 8588 CD Soprofilm, Brussels
© 02- 242 5928 CD Bolex, Yverdon © 024-216-021 <® Cinequip, Toronto © 416-467 7700; Lome

Lapham, Vancouver © 604-738 5200 (EDProfessionelt Film/Videocenter, Copenhagen © 0033- 931397
CDRosco, Madrid ©01 -246-1102 CDDimaphot, Paris© 01 -4723 9887 ODTelefex, London ©01 -569 9595
(DCentury EPE, Athens ©01-6461332 CDDe Sisti, Rome ©06 2010166 GDSanwa, Tokyo ©03-404 0366
<®>Solimac, Petaling Jaya © 03-757 7872 (SDCompactlight, Amsterdam © 020-935 807 (©Professional
Lighting Services, Auckland © 09-774 895 CDRosco, Sacavem © 01-947 2237 CD Rune Ericson Film AB,
Solna © 08-734 0845 dDCinerent, Helsinki © 0-651330.
USA Distribution: Dedotec USA, 210 Westlake Drive,
fax. (914)761-9501.
14

Marketing: Dedo Weigert Film GmbH, RottmannstraBe 5, 8000 Munchen 2,

(89) 52 50 64, fax (89) 52 9173.

▲

Send questions pertaining to
cinematography to Ask ASC, American
Cinematogrpaher, P.0. Box 2230, Hol¬
lywood, CA 90078.

American Cinematographer - August 1990

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