ASTM E1347, titled “Standard Test Method for Color and Color-Difference Measurement by Tristimulus (Filter) Colorimetry,” is a standard that establishes procedures for measuring color using tristimulus colorimeters. This method is used for a variety of applications where precise color evaluation is necessary, including research and development, quality control, and product comparisons.
The standard specifically outlines the use of colorimeters, which utilize filters to simulate the human eye’s response to light and measure the reflected or transmitted color of materials. By adhering to ASTM E1347, industries can achieve consistent color matching and maintain the integrity of their products’ visual appearance.
Color Measurement Equipment: The standard specifies the use of a tristimulus colorimeter equipped with appropriate filters that correspond to the color perception curves of the human eye. These instruments provide values in terms of the CIE XYZ or CIE LAB color spaces, which represent the color’s characteristics in a standardized format.
Sample Preparation: Proper sample preparation is crucial for accurate color measurement. ASTM E1347 outlines that the sample should be clean and free of any surface contamination, as dirt, dust, or oils can affect the measurement. Consistent sample thickness and surface texture are also important to ensure repeatability.
Measurement Conditions: The standard dictates that color measurements be taken under controlled lighting conditions. This often involves the use of standardized illuminants, such as D65 (daylight) or C (average north sky daylight), to ensure that color readings are not influenced by ambient lighting variations.
Measurement Procedure: The test involves placing the sample in the measurement area of the colorimeter. The instrument then measures the reflected or transmitted light through its filters, which correspond to the red, green, and blue (RGB) regions of the visible spectrum. The resulting data is used to calculate the sample’s color properties.
Data Interpretation: ASTM E1347 provides guidelines for interpreting the color measurement data. This includes calculating color differences using standardized equations, such as ΔE (delta E), which quantifies the perceptual difference between a reference color and the sample color.
Plastics and Polymers: In the plastics industry, maintaining color consistency is crucial, especially for products like consumer goods, automotive parts, and packaging materials. ASTM E1347 helps manufacturers monitor and control color variations, ensuring that every product batch matches the desired specifications.
Coatings and Paints: Paint and coating manufacturers use ASTM E1347 to assess the color quality of their products. It allows for precise color matching during the formulation process and helps identify any deviations from the target color in the final product.
Textiles: For the textile industry, color measurement is essential to maintain the quality of dyed fabrics. ASTM E1347 ensures that colors remain consistent across different production runs and under various lighting conditions.
