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P.O. Box 716
Sunapee, NH 03782-0716
603-526-2420 (office), 603-526-2729 (fax)

Goniometric (spectral)

Goniometric (photometric)


Gloss and Reflectance

Haze and Clarity

Online Systems
  Glossmeter GR-2
  Glossmeter GR-4
  Color CMTS-5000
  Color CMTS-5000T
  Hazemeter HMS-3
  Transmittance TM-100M


The Murakami Team
Murakami Products
Avian Technologies LLC
Murakami Corporate


GSP-1B and GCMS-3B

GCMS-3B Gonio-spectrophotometric
Color Measurement System
(includes computer and GPIB interface)


Instrument alone:
GSP-1B Gonio-spectrophotometer

The GCMS-3B system is designed for measuring gonio-apparent materials. These are materials that change color appearance depending on the viewing and illumination angles. Examples are pearl-mica coating surfaces and interference pigments. For these types of materials, this gonio-spectrophotometric color measurement system can measure its color by measuring the spatial distribution of reflected (or transmitted) light at user-selectable angles of illumination and detection.

Based on the precise control on the incident and acceptance angle, the measurement of the spectral distribution of every pair of illumination and detection angles are performed individually. After calibration and mounting of the samples, the settings for measurement conditions are made. Once the measurement begins, the operations of the instrument are completely automatic, and color system proceeds to capture spectral reflectance data at each angle pair selected. Measurement states can be saved to file and retrieved for repeating the same sets of angle pairs.

The data achieved by this kind of measurement can be widely used as the basic data in the development of gonio-apparent material matching. The data can also be applied as the input to computer graphics rendering models.

The GCMS-3B can make measurements of a wide variety of gonio-chromatic applications including:

  • Pearl-mica and metallic paints
  • Anodised and metallised coatings and inks
  • Hair treatments – colorants and conditioners
  • Coated Glass
  • Plastics
  • Retro-reflective, coated and pearl-effect textiles
  • Cosmetics
  • Liquid-crystal displays

click image for a larger version

Operational Information

The sample to be measured (5) is clamped into place on the sample stage with manually-adjustable tilt (“flop”) angle (3). This stage accepts samples up to 195 x 220 mm and has a broad aperture to allow a wide range of incident and viewing angles. Fine adjustment of the flop angle can be made by the micrometer assembly (4). During calibration, the sample is replaced by a barium sulphate-coated white standard plate.

The reference white plate (6), also barium sulphate-coated, is positioned in its receptacle and remains in place throughout routine reflectance measurements.

The entire sample platform (2) rotates in accordance with the parameter settings made in the software, between limits of -80° and +80° from the normal (perpendicular to the sample plane).

The lamp housing (1) incorporates a single tungsten halogen source lamp which is divided into two identical beams via mirrors, lenses and heat filters. The sample beam (1S) and reference beam (1R) exit through apertures. The lamp housing rotates on the same axis as the sample platform to provide a variable incident angle, again within the range of ± 80° from the normal.

The light reflected from the sample, and that from the reference white plate enter the sample receptor (7S) and reference receptor (7R) respectively. Each beam is directed to the fixed detection system via a mirror and through a beam chopper assembly. The chopper alternately directs the reference beam and the sample beam to the monochromator via a lens system.

The light from the monochromator is dispersed into each wavelength via a diffraction grating and then is photoelectrically converted by the elements of a photodiode array. The electrical signals are amplified by a wavelength-independent amplifier, transformed to digital signals by an A/D converter, and then transmitted to the PC via a GP-IB IEEE interface for processing into the user-selected colour scales and displays.

click image for a larger version


Measuring SystemDual-Beam Optics with Reference Plate
Measuring GeometryAdjustable illumination and viewing angles
Light Source12V 100W Halogen Lamp
Lamp Life1000 hrs Nominal
Dispersing elementConcave Diffraction Grating
DetectorSilicon Photodiode Array
Wavelength Range390 – 730 nm
Wavelength Interval10 nm
Spectral Bandpassapprox. 10 nm
Wavelength Accuracy± 1 nm @ 560nm
Wavelength Repeatability± 0.1 nm
Incident Angle Range-80° to +80° **
Receiving Angle Range-80° to +80° **
 ** lamp housing obstructs receptor when difference between incident angle and receiving angles <= 12°
Angular Accuracywithin ± 0.5°
Angular Resolution0.1° (resolution of absolute encoder)
Viewed Areaapprox. 8 x 16 mm at 0° receiving angle
approx. 8 x 94 mm at 80° receiving angle
(both with flapping angle = 0°)
Source Aperture Angle±1.05° in plane of measurement
±2.10° perpendicular to plane of measurement
Receptor aperture± 1° in circle
Neutral Density Filter RangeReduces sample to 30, 10, 3, 1, 0.3, 0.1, or 0.03%
Measurement Durationapprox. 3 seconds per angle increment
Measurement Accuracywithin ± 0.5%
Repeatability0.05% SD ( white tile measured 45°/0° at 560nm)
Dimensions (mm)566 (W) x 972 (D) x 922 (H)
Power Requirements100V AC, 50/60 Hz, 4A (for Europe, 220 - 240V AC, 1KVA transformer recommended)
Computer InterfaceGP-IB (PC) F by Contec Ltd
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