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1198 Chapter 15: Lights and Cameras
color is visible in the color swatch next to the
temperature spinners.
Filter—Useacolorfiltertosimulatetheeffectof
a color filter placed over the light source. For
example, a red filter over a white light source
casts red light. Set the filter color by clicking
the color swatch to display the
Color Selector
(page 1–157)
. Default=white (RGB=255,255,255;
HSV=0,0,255).
Intensity group
These controls specify the strength or brightness of
photometric lights in physically based quantities.
You set the intensit y of a light s ource using one of
the following units:
lm (lu men)—Measures the over all output power
of the light (
luminous flux (page 3–1049)
).
A 100-watt general purpose light bulb has a
luminous flux of about 1750 lm.
cd (candela )—Measures the maximum
luminous intensity (page 3–1059)
of the light,
usually along the direction of aim. a 100-watt
general purp ose light bulb has a luminous
intensity of about 139 cd.
lx at (lux)—Measures
illuminance (page 3–1049)
caused by the lig ht shining on a surface at a
certain distance and facing in the direction of
thesource.TheluxistheInternationalScene
unit, w hich is equivalent to 1 lumen per square
meter. The AS unit for i l luminance is the
footcandle (fc) which is equivalent to 1 lumen
per square foot. To convert from footcandles to
lux, multiply by 10.76. For example, to specify
an illuminance of 35 fc, set illuminance to 376.6
lx.
To specify t he illuminance of a light, you must
set the lx value, and enter the distance at which
that illuminance is measured.
Note: You can obtain these values directly from
lighting manufacturers. A table of some common
lamp types is provided in
Photometr ic Lights:
Common Lamp Values (p age 2–1174)
.
Linear Light Parameters Rollout
Create panel > Lights > Create a photometric linear lig ht.
> Linear Light Parameters rollout
Selec t a linear light. > Modify panel > Linear Light
Parameters ro llout
The Linear Light parameters rollout lets you set
the length of your photometric linear light.
See also
Photometr ic Lights (page 2–1155)
Target Linear Light (Photometric) (page 2–1159)
Free Linear Light (Photometr ic) (page 2–1160)
Interfa ce
Lengt h—Sets the length of your linear light.
Area Light Parameters Rollout
Create panel > Lights > Create a photometric area light. >
Area Light Parameters rollout
The Area Light parameters rollout lets you set the
dimensions of your photometric area light.
See also
Photometr ic Lights (page 2–1155)
Target Area Light (Photometric) (page 2–1161)
Free Area Light (Photometric) (page 2–1162)