ASTM E Calculating Yellowness and Whiteness Indices from Instrumentally. Measured Color Coordinates. This practice provides numbers that correlate. Yellowness indices are used chiefly to measure these types of degradation. Yellowness Index per ASTM Method E is calculated as follows. To begin the ASTM D is a now obsolete Yellowness Index specification that is locked to calculate only using C/2 (illuminant C, 2deg.
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For example, a series of specimens to be compared should have generally similar gloss, texture, and if not opaque thickness, and translucency. Whiteness Whiteness is defined as a measure of how closely a surface matches the properties of a perfect reflecting diffuser, i.
Yellowness Index (YI) ASTM E
The idea was that chromaticity factor G-B required three times the weighting of the lightness factor G of the lightness. Auditing Consulting Sourcing Training. After specifying the illuminant, observer angle, and the reference color, the test sample is inserted into the specimen holder, and the spectrophotometer takes the reading.
Yellowness, as defined by ASTM Ehas been applied successfully to a variety of white or near-white materials, including paints, plastics, and textiles. Certification Astmm confirming that your products and services meet all trusted external and internal standards.
Because visual observing conditions can vary widely, users should compare calculated indices with visual estimates to ensure applicability. Assurance Testing Inspection Certification. This test is most commonly used to evaluate color changes in a material caused by real or simulated outdoor exposure.
For the purposes of this standard, the color of such a surface is known as preferred white. Stensby — based on Hunter Lab color coordinates. Comparable values between two instruments can be obtained only when both are measured with the same light. Multiple samples should be measured and the readings averaged. Inspection Validating the specifications, value and safety of your raw materials, products and assets. The optical lightener is effective only due to the UV radiation.
It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Yellowness according to ASTM E D was developed specifically for determining the yellowness of homogeneous, non-fluorescent, nearly colorless, transparent, nearly white translucent, or opaque plastics, as viewed under daylight lighting conditions. Testing Evaluating how your products and services meet and exceed quality, asym, sustainability astk performance standards.
Evaluating how your products and services meet and exceed quality, safety, sustainability and performance standards. Its derivation assumed that, because of the limitation of the concept to yellow or blue colors, it was necessary to take account of variations in the amber or red colorimeter readings.
It can also be applied to materials other than plastic fitting this description. Since YI testing is often a series of comparative measurements over extended periods of time, these factors should be defined and documented prior to any testing.
The greater the illumination intensity in the UV-range, the more the greater the detection of the optical lightener. In general, specimens should ast prepared and presented for measurement in the manner that is standard for the test being performed.
Yellowness Index (YI) ASTM E313
For near-white specimens, however, it is often useful to calculate single-number scales of yellowness or whiteness. However, the equation is commonly used with other illuminants; therefore the value shown will depend on the primary illuminant you have chosen.
Test sample packaging, handling, and preparation preferably no cleaning can affect the test results by modifying the surface of the sample. It should be clear that the distribution of relative spectral radiation of the light on the sample during measurement plays an important role.
In the case of non lightened asfm, standard illuminant C, i.
Historical Version s – view previous versions of standard Translated Version s: Standards can be obtained from appropriate standard authorities. For whiteness measurement, this practice is limited to specimens having Munsell value greater than 8. White textiles, paints, and plastics are a few of the materials that can be described by the indices of yellowness or whiteness calculated by this practice.
No other units of measurement are included in this standard. Through our network of over 43, people in 1, laboratories and offices in countries, Intertek provides quality and safety solutions to a wide range of industries e31 the world.