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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The optical lightener is effective only due to the UV radiation. Yellowness Index is a number calculated from spectrophotometric data that describes the change in color of a test sample from clear or white to yellow. The indices can be calculated, rounded, and adjusted in the last retained significant digit to minimize the residual error in the white point values.
Standard ISO specifies a half peak width of 44 nm. For near-white specimens, f313, it is often useful to calculate single-number scales of yellowness or whiteness. 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. This practice provides recommended equations for such scales and discusses their derivations and uses, and limits to their applicability see also Ref 1 2. For whiteness measurement, this practice is limited to specimens having Munsell value greater than 8.
Stensby — based on Hunter Asgm color coordinates. The ISO brightness value indicates the blue reflection of the paper.
The effect occurs at approximately nm; maximum radiation is at approximately nm. This test is most commonly used to evaluate color changes in a material caused by real or simulated outdoor exposure. Need help or have a question? Some standards addressing the visual estimation of color and color difference are Practices DDEand Eand Guide E In general, specimens should be prepared and presented for measurement in the manner that is standard for the test being performed.
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Whiteness and Yellowness Indices in a SpectroEye
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 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. It entails a filter with a maximum transmission curve of nm wavelength lambda and a specific half peak width.
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Yellowness Index (YI) ASTM E
Inspection Validating the specifications, value and safety of your raw materials, products and assets. Send us a request Wilton UK: Values greater than indicate a astmm white, while values less then indicate a yellowish white. CIE Whiteness — Some disadvantages of the previously-mentioned indices is that a whiteness that is calculated with this formula does not differ if the measured sample has a color drift or is just less white.
Historical Version s – view previous versions of standard Translated Version s: The color deviation number Tw shows additionally, if there is a red hue negative value of Tw or a green hue positive value of Tw. Auditing Consulting Sourcing Training. Select enough specimens or specimen areas to provide an average result that is representative of each sample to be tested.
Yellowness Index (YI) ASTM E313
However, the equation is commonly used with other illuminants; therefore the value shown will depend on the primary illuminant you have chosen. Historical Version s – view previous versions of standard. Multiple samples should be measured and the readings averaged. Whiteness Whiteness is defined as a measure of how closely a surface matches the properties of a perfect reflecting diffuser, i.
Evaluating how your products and services meet and exceed quality, safety, sustainability and performance standards. E13 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 around the world. Assurance Testing Inspection Certification.
Whiteness and Yellowness Indices in a SpectroEye
This method is based on the use of colorimeter readings B and G. The idea was that chromaticity factor G-B required three times the weighting of the lightness factor G of the lightness. Global Gateway Please select your desired language.
Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of xstm standard. Yellowness, as defined by ASTM Ehas been applied successfully to a variety of white or near-white materials, including paints, plastics, and textiles. However, the equation is commonly used with other illuminants and observer functions, therefore the value shown will depend on the primary illuminant and the observer function you have chosen.
Because visual observing conditions can vary widely, users should compare calculated indices with visual estimates to ensure applicability.