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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Stensby — based on Hunter Lab color coordinates. The optical lightener is effective only due to the UV radiation.
Select enough specimens or specimen areas to provide an average result that is representative of each sample to be tested. In the case of non lightened samples, standard illuminant C, i.
Ee313, this also intensifies ISO brightness. Historical Version s – view previous versions of standard. The idea was that chromaticity factor G-B required three times the weighting of the lightness factor G of the lightness.
Global Reach Intertek is the industry leader with over 42, asgm in 1, locations in over countries. Inspection Validating the specifications, value and safety of your raw materials, products and assets. Link to Active This link will always route to the current Active version of the standard. Values greater than indicate a bluish white, while values less then indicate a yellowish f313.
Multiple samples should be measured and the readings averaged.
For whiteness measurement, this practice is limited to astmm having Munsell value greater than 8. Some standards addressing the visual estimation of color and color difference are Practices DDEand Eand Guide E Assurance Enabling you to identify and mitigate the intrinsic risk in your operations, supply chains and business processes. For example, a series of specimens to be compared should have generally similar gloss, texture, and if not opaque thickness, and translucency.
Whiteness and Yellowness Indices in a SpectroEye
Send us a request Wilton UK: For the purposes of this standard, the color of such a surface is known as preferred white. Need help or have a question? This test is most commonly used to evaluate color changes in a material caused by real or simulated outdoor exposure. Validating the specifications, value and safety of your raw materials, products and assets. Referenced Documents purchase separately The documents listed below are referenced e331 the subject standard but are not provided as part of the standard.
Testing Evaluating how your products and services meet and exceed quality, safety, sustainability and performance standards. Because visual observing conditions can vary widely, users should compare calculated indices with visual estimates to ensure applicability. 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.
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. However, the equation is commonly used with other illuminants; therefore the value shown will depend on the primary illuminant you have chosen.
Standards can be obtained from appropriate standard authorities. Evaluating how awtm products and services meet and exceed quality, safety, sustainability and performance standards. Standard ISO specifies a half peak width of 44 nm. 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.
Through our network of over 43, people in 1, laboratories and offices in d313, Intertek provides quality and safety solutions to a wide range of industries around the world.
Assurance Testing Inspection Certification. Whiteness Whiteness is defined as a measure of how closely a surface matches the properties of a perfect reflecting diffuser, i.
Whiteness and Yellowness Indices in a SpectroEye
No other units of measurement are included in this standard. Historical Version s – asm previous versions of standard Translated Version s: 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. The color deviation number Tw shows additionally, if there is a red hue negative value of Tw or a green hue positive value xstm Tw.
The greater the illumination intensity in the UV-range, the more the greater the detection of the optical lightener. For near-white specimens, however, it is often useful to calculate single-number scales of yellowness or whiteness.