PSA D15 5083 Opaque Colored Products - Color Point (Spectrocolorimetry)

The standard “PSA D15 5083 Opaque colored products - Color point (spectrocolorimetry)” developed by the PSA Peugeot Citroen group describes a working method for determining the color point in the visible range of opaque colored products. This method is mainly applicable to plastic parts, textiles, leather upholstery and plain paints (opaque), luminescent materials and metallic or pearlescent paint coatings are excluded from the scope of this method.

Surface appearance parameters interact with color and are included in color point measurements (such as gloss, tension, graining of plastic parts, striation of textiles, crushed velvet).

From the reflectance measurements carried out according to the formulas given in the standard, by means of a spectrocolorimeter with an integrating sphere, over the entire visible spectrum between at least 400 and 700 nanometers, the three color components of the color point X, Y, Z are determined.

For the purposes of this standard, the following terms and definitions apply:

• Trichromatic components refer to the amount of each of the three primary or reference stimuli that, when mixed, create an equivalent stimulus.
• The specular component refers to the reflected radiation symmetrically with respect to the right angle to the incident radiation.
• The illuminator is the light source recommended for general colorimetry and for which the relative spectral distributions of energy are known.
• Reflectance is the ratio of the brightness between a non-emissive surface and a perfect diffuser in terms of wavelength.
• The observer is the receiver of radiation associated with a given trichromatic system and whose colorimetric properties are defined by the spectral trichromatic components of the system.
• An integrating sphere is a sphere with an inner surface covered with a white diffuser coating that allows a surface to be illuminated or observed in all directions.
• Luminance is the concept of brightness from black to white.
• Chroma is the quality of color perception that expresses the proportion of pure color within a complete sensation.
• Tone is the visual sensation quality that gives rise to dominant colors such as blue, green, and yellow.

The spectrocolorimer used in these tests is placed in a dust-free and air-conditioned room and on a vibration-free support. The power supply is fixed to prevent any slippage. This equipment consists of the following elements:

• Integrating sphere with possibility to include or exclude mirror component
• Diffused lighting system
• Near vertical observation system (0 to 8 degree angle)
• Illuminant D65 and A (to measure metamerism)
• Standard observer 10 degrees
• Visible spectral area from 400 to 700 nm (minimum recording every 10 nm)
• Halogen lamp that must be systematically replaced every 2000 hours

These tests also use a computer system to control the spectrocolorimeter, display reflectance curves, and analyze measurements.

The following standards are required to calibrate the spectrocolorimeter:

• Black standard 0 percent: Consists of a light trap.
• Approved white standard: Ceramic, white porcelain or barium sulphate disk with spectral chart.
• Intermediate standards made of ceramics in various colours to check calibration.

For calibration, the inclusion or exclusion of the specular component is selected and the position of this component on the spectrocolorimeter is checked. The largest possible aperture is selected according to the test samples to be measured. The spectrometer is calibrated according to the supplier's procedure at the beginning of each half-day minimum period.

While preparing test samples, if necessary, the test samples are wiped using the equipment before taking measurements.

During measurements, 10 degrees are selected on the illuminator and the observer. An area as flat as possible is selected on the test sample. According to the procedure specific to the spectrocolorimeter, at least five measurements are made in various parts of the selected area and in various orientations with angular rotations.

The average of five measurements determines the three color components of the color point X, Y, Z. The computer system allows these components to be expressed in the CIE 1976 colorimetric space. The standard variation is calculated for each component according to the formula given in the standard.

The results of a measurement should always be analysed in the form of colorimetric variations in accordance with the test method described in the standard “D15 5084 Opaque or transparent coloured products - Calculation of colorimetric variations”.

In addition to the results obtained, the test report should include the type of equipment used, the size of the measuring aperture, whether specular radiation is included or not, the type of illuminator, the exact reference of the test sample, the description of the measuring area (size, location) and similar information.

Among the numerous testing, measurement, analysis and evaluation studies that our organization has carried out for businesses in various sectors, it also provides certification and testing services defined in the “PSA D15 5083 Opaque colored products - Color point (spectrocolorimetry)” standard with its trained and expert staff and advanced technological equipment.