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Because the eye is a highly complex organ, this
is by no means a simple task. It involves the meeting of many disciplines:
psychology, physiology, and physics among them.
Photometry can be said
to have become a modern science in 1924, when the Commission Internationale
de l’Eclairage
(CIE) met to define the response of the average human eye. The Commission
measured the light-adapted eyes of a sizable sample group, and compiled
the data into the photopic curve. Simply stated, the curve reveals
that people respond strongest to the color green, and are less sensitive
to the spectral extremes, red and violet.
The eye has an altogether
different response in
the dark-adapted state, wherein it also has difficulty determining
color. This gave rise to a second set of measurements, and the scotopic
curve.
Having defined the eye’s spectral response,
CIE sought a standard light source to serve as a yardstick for luminous
intensity. The first source was a specific type of candle, giving
rise to the terms footcandle and candlepower. In an effort to improve
repeatability, the standard was redefined in 1948 as the amount of
light emitted from a given quantity of melting platinum.
Photometers
· System
S350 Power/Energy Meter
· System S370 Single-Channel Photometer
· System S380 Dual-Channel Photometer
· System S471 Portable
Optometer (New Handheld Optometer)
Photometric Sensor Heads And Accessories
· Model 211 Illuminance
Sensor Head
· Model 263 Illuminance Sensor Head
· Model 268P Low-Profile Illuminance
Sensor Head
Luminance Measurement Heads And Accessories
Each of these sensor heads is provided with a photometric
filter and cosine diffuser. The Model 211 is UDT Instrument's "universal" photometric
head, as it adapts for use with most accessories. The Model 263 is
a scaled-down version of the 211 suited for field measurements. And
for applications with limited mechanical clearance, we offer the
low-profile Model 268P.
· Model 1153 Lumilens
· Model 114 Steradian Shade
· Model 116/Model 124 Luminance
Probes
· Model 2153 Brightness Sensor
CRT Measurement Heads CRT Brightness Sensor
· Model 1120 Reflex
Viewing Module
· Model 265 CRT Brightness Sensor
Sensor Heads For LED And Point-Source Measurements
Amplifiers TRAMP
Housing, Stands And Adapters
· Model 102 Filter
Holder
· Model 103 Standard Lab Stand
· Model 104 Filter Holder And Coupler
· Model 108 Male Coupler
· Model 109 Heavy-Duty Lab Stand
· Model 110 Sensor Holder And Aperture
Set
· 1706 Tabletop Tripod
Application Software Computer-Controlled Photometric Measurements
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