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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
Model S350
Optometer
Model S370 Single-Channel Optometer
Model S380 Dual-Channel Optometer
Model S471 Portable 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 Instruments' "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
Model
1120 Reflex Viewing Module
Model 265 CRT Brightness Sensor
Sensor Head For LED And Point-Source Measurements
Model 224 Sensor Head
Amplifiers
TRAMP Amplifier
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 |
