PR-655/670 User Manual
19
O
PTICAL
A
CCESSORIES
The following optical accessories can be added to your existing PR-655 or PR-670. They require calibration with
the instrument to provide accurate results. They can be calibrated by the user using the User Self Calibration
software.
N
EUTRAL
D
ENSITY
(ND)
F
ILTERS
Neutral density filters are used to attenuate the incoming optical radiation (light level). They can be used on
applications where the light source may saturate the instrument causing the PR-
655/670 to report a “
Light
Overload”
condition. ND filters can be mounted on the standard MS-75 lens or the optional SL-1X lens.
The following table lists all available ND filters and their respective characteristics.
Neutral Density Filter
Signal Attenuation
% Transmission
ND-0.3
2
50
ND-0.7
5
20
ND-1
10
10
ND-2
100
1
ND-3
1000
0.1
TABLE 6 - NEUTRAL DENSITY FILTERS FOR THE PR-655/670.
Reflectance Standard
The 2” diameter (51 mm) PTFE reflectance
standard can be used for making ambient light measurements,
measurements of point sources (e.g. lamps) or measurements of the illuminating source for reflectance or
L*a*b* calculations. The reflectance standard features a Society of Automotive (SAE) ¼ - 20 threads, black
anodized, aluminum case for mounting to an optical table.
RS-3
The RS-3 is an un-calibrated reflectance standard - all spectral reflectance correction factors are set to 1.00.
SRS-3
Spectrally Calibrated Reflectance Standard for absolute spectral reflectance - includes reflectance factors and
certificate of calibration.
