Reflectance and Transmission Test Solutions

Specular and Diffuse Reflectance Measurement Systems for Measuring Virtually Any Sample

Gamma Scientific provides unique, high performance solutions for reflectance and transmission testing. These systems capture complete spectral and colorimetric properties of thin film coatings with scan times typically less than one second. Uniquely the 191F Specular Reflectometer can measure first-surface reflectance on transparent substrates up to 0.3mm thick, with 100% exclusion of backside reflectance with no backside preparation, non-contact and non-destructively. Second-surface or second layer intermediate reflectance can also be characterized on intermediate surfaces by excluding reflectance from other surfaces within the substrate. 

Reflectance and Transmission test systems are available in several configurations, optimized for the sample type and desired measurement result, including either polished (specular) or rough (diffuse) samples. The below product selection guide will help you configure the best system to fit your needs.



  • Anti-reflectance coating characterization
  • Flat-panel display glass testing
  • Touchscreen display glass testing
  • Optical filter / lens testing
  • Pyrolytic glass coating test & characterization
  • Characterization of flat panel displays, photovoltaic coatings, low-E architectural coatings, paint samples and diffuse plastics


Reflectance Testing White Paper

Thin Film Testing White Paper

The vast majority of our Display Measurement Solutions are custom-configured.

Installation and commissioning is optional, though for the automated systems, highly recommended.

191F Series models are available in handheld, tabletop, semi-automatic and fully automatic configurations.

191F Series models have a fixed AOI as indicated above.  A handheld unit with 10-45º variable AOI is available under model number 191C.

191 T and 191 DR Series units are available in tabletop models only.


191 Series Optical Heads Specification Comparison Table
191 Series Optical Heads 191F 191T 191C 191DR
Measurement Type Specular Reflection
or Total Reflection
Total Transmission Specular Reflection Diffuse Reflection
Sample Types Glass, Plastic, Metal,
Polished Substrates
Glass, Plastic,
Transmissive Elements
Glass, Plastic, Metal,
Polished Substrates
Opaque Materials,
Matte Surfaces,
Rough Substrates
Illumination Angle Fixed Angle at
0°, 10°, 20°, or 45° or
Dual Angle 10° & 45°
10° to 45° Variable 45°
Viewing Angle Matches Selected Illumination
2π (180°) 10° to 45° Variable 45°
System Configuration Handheld, Tabletop,
Semi-Automatic, Fully Automated
Tabletop Handheld Tabletop (Sphere Based)
Minimum Sample Thickness Dependent on Angle
(transparent samples)
(transparent samples)
1.5mm (transparent samples)
None (opaque samples)
None (opaque samples)
Spectral Range 365nm-900nm (default)
UV / IR Options
365nm-900nm (default)
UV / IR Options Available
365nm-900nm 365nm-900nm
UV / IR Options Available
Illumination Spot Size
(Area of Analyis)
1mm x 10µm Ø 1mm, Ø 2mm, or
Ø 3mm
1mm x 65µm Ø 1mm, Ø 2mm, or
Ø 3mm
Typical Measurement Speed
(Sample Dependent)
≈500-1000ms ≈1000-3000ms ≈2000-15000ms ≈1000-3000ms
Optical Head Dimensions Varies Depending
on Model/Angle
Height: 350mm (13.75″)
Width: 205mm (8.0″)
Depth: 225mm (8.85″)
Weight: 3.5kg (7.75lbs)
Height: 230mm (9″)
Width: 150mm (6″)
Depth: 150mm (6″)
Weight: 1.6kg (3.5lbs)
Height: 300mm (12″)
Width: 1000mm (40″)
Depth: 300mm (12″)
Weight: 12kg (25lbs)
Spectral Reflectance/
Spectral Transmission
± 0.2% ± 0.5% ± 0.5% ± 0.5%
(CIE 1931 X, Y, Z)
± 0.05 ± 0.05 ± 0.05 ± 0.05
(CIE 1931 x,y)
± 0.002 ± 0.005 ± 0.005 ± 0.005
LAB Color
(CIE 1976 L*, a*, b*)
L* ± 1.0 a*, b* ± 0.8 L* ± 2.0 a*, b* ± 0.8 L* ± 2.0 a*, b* ± 0.8 L* ± 2.0 a*, b* ± 0.8
Reported Parameters
Spectral Data Reflectance/Transmission as a function of wavelength
Colorimetric Data CIE Tristimulus X, Y, Z, with 2° or 10° View Angle, (L*, a*, b*), (x, y), (u’, v’), and other parameters
Illuminant Weighting Illuminant A, Illuminant B, Illuminant C, Illuminant D65, or User Specified Custom Illuminant
Specifications are subject to change without notice.
The 191F Reflectance Measurement Heads are available in fixed angle of incidence configurations ranging from 0 to 45º. A handheld unit with variable angle of incidence is also available, please...
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