DESCRIPTION
With our Visible Light Reflectance Test service, we may use any number of color coordinate systems, the primary being the CIE L*a*b* system.
The L * value indicates the Level of Light- Dark. (0 – 100)
the a* value Redness or Greenness (-100 = Green; +1-00 = Red)
the b* value Yellowness or Blueness (-100) = Blue; +100 = Yellow)
The two measures calculated are:
1) DELTA E which is obtained by the formula
√((L*-L*)² + (a*-a*0)² +(b*-b*0)²) (1)
The Delta E value merges the overall color change into a parameter that provides a single overall value of change from the baseline.
Where L*, a* and b* are the CIE colorimetric parameters such that the L * value indicates the Level of Light- Dark, the a* value Redness or Greenness, and the b* value Yellowness or Blueness.
The delta E is always positive (or zero) and a value less than 2.0 is generally considered as a change
of color that is less than what the human eye can distinguish.
2) The Yellowness Index YE313 (per ASTM E313)
The Yellowness Index (ASTM E313) characterizes the amount of “Yellowing,” on a scale of -100 (saturated blue to +100 saturated yellow
Test Standards:
Include, but are not limited to:
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ASTM G 151 – 97 “Standard Practice for Exposing nonmetallic materials in accelerated test devices that use laboratory light sources,”
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ASTM G-155-05a “Standard practice for Operating Xenon Arc Light Apparatus for Exposure of Non-Metallic Materials,”
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ASTM D 2565 – 99 “Standard practice for Xenon-Arc exposure of plastics intended for outdoor applications,”
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ASTM D 4459 – 99 “Standard practice for Xenon-Arc exposure of plastics intended for indoor applications,”
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ASTM D5071 – 06 “Standard Practice for Exposure of Photodegradable Plastics in a Xenon Arc Apparatus,”
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ASTM D4329 – 05 “Standard Practice for Fluorescent UV Exposure of Plastics,”
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ASTM D5208-09 “Standard Practice for Fluorescent Ultraviolet (UV) Exposure of Photodegradable Plastics,”
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ASTM D 4674 – 89 “Standard test method for accelerated testing for color stability of plastics exposed to indoor fluorescent lighting and window-filtered daylight,”
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ASTM D3424 − 11 “Standard Practice for Evaluating the Relative Lightfastness and Weatherability of Printed Matter,”
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ASTM D4303-03 “Standard Test Methods for Light fastness of Colorants Used in artists’ materials,”
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ASTM D4587-11 “Standard Practice for Fluorescent UV-Condensation Exposures of Paint and Related Coatings,”
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ASTM D750- 06 “Standard Test Method for Rubber Deterioration Using Artificial Weathering Apparatus,”
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ASTM D6695 – 08 “Standard Practice for Xenon-Arc Exposures of Paint and Related Coatings,”
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ASTM G147 “Standard Practice for Conditioning and Handling of Nonmetallic Materials for Natural and Artificial Weathering Tests,”
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ASTM ISO 4892-2 “Plastics – Methods of exposure to laboratory light sources – Part 2 Xenon arc sources,”
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ASTM ISO 4892-3 “Plastics – Methods of exposure to laboratory light sources – Part 3 Fluorescent UV lamps,”
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ASTM ISO 11341 “Paints and varnishes – Artificial weathering and exposure to artificial radiation – Exposure to filtered xenon-arc radiation,”
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ASTM BS EN ISO 105-B02:1999 “Color fastness to artificial light: Xenon arc fading lamp test,” ASTM D6695 − 16 Standard Practice for Xenon-Arc Exposures of Paint and Related Coatings.
Color Test Standards:
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ASTM E308-08 “Computing the colors of objects using the CIE system,”
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ASTM E313-05 “Standard Practice for Calculating Yellowness and Whiteness Indices from Instrumentally Measured COLOR Coordinates (Abstract only),”
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ASTM E1347 – 06 “Standard Test Method for Color and Color-Difference Measurement by Tristimulus Colorimetry,”
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ASTM D1729 “Practice for Visual Appraisal of Colors and Color Differences of Diffusely-Illuminated Opaque Materials,”
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ASTM D6290-13 “Standard Test Method for Color Determination of Plastic Pellets UV Exposure Tests.”
UPF Standards:
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AATCC TM183-2010 “Transmittance or Blocking of Erythemally Weighted Ultraviolet Radiation through Fabrics,”
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ASTM D6544 “UPF Standard Practice for Preparation of Textiles Prior to Ultraviolet (UV) Transmission Testing,”
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ASTM D6603 “Standard Specification for Labeling of UV-Protective Textiles,” AS_NZS_4399 “Sun protective clothing— Evaluation and classification,”
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BS EN 13758-1 “Textiles – Solar UV protective properties – Method of test for apparel fabrics,”
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GBT18830-2009 “Textiles – Evaluation for solar ultraviolet protective properties,”
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ISO 12312-2:2015 Eye and face protection - Sunglasses and related eyewear - Part 2: Filters for direct observation of the sun (ISO 12312-2:2015).