Significato e uso
5.1 This practice should only be used to compare samples of the same material and the same general appearance. Per esempio, a range of specimens to be compared should have roughly similar lustre, texture and (if not opaque) thickness and semi-transparency.
5.2 For yellowness measurements, this practice is limited to samples whose main wavelength is in the range 570 to 580nm or whose Munsell hue is approximately 2.5GY to 2.5Y. For whiteness measurements, this practice is limited to samples with Munsell values greater than 8.3 (CIEY greater than 65) and Munsell chromaticity no greater than 0.5 (B tone) and Munsell chromaticity no greater than 0.5 (Y tone 0.8) and all other tones of 0.3 (Vedere 3.3.1).
5.3 The combination of measurement and calculation that results in a yellow or white index is a psychophysical process, questo è, the specified procedure is designed to provide numbers relevant to visual estimates made under specific typical observation conditions. Since visual observation conditions vary widely, users should compare the calculated index with visual estimates to ensure applicability. Some standards that address color and chromatic aberration vision estimation are Practices D1535, D1729, E1360, and E1541, as well as guidelines E1499.
5.4 This practice does not include specimen preparation, a procedure that can have a significant impact on the amount measured. Tipicamente, samples should be prepared and presented for measurement in a standard manner for the tests performed. Select enough samples or sample areas to provide average results representative of each sample under test. See Practice E1345.
Calcolo dell'indice di giallo e dell'indice di bianco utilizzando coordinate di colore strumentali
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1.1 This practice provides numbers associated with visual ratings of yellow or white for color specimens of white and near-white or colorless objects, viewed in daylight by observers with normal color vision. White textiles, paints and plastics are some of the materials that can be described by the yellow or whiteness index calculated in this way.
1.2 In order to perform a complete analysis of object color by a specified observer and a specified light source, three parameters need to be used. Tuttavia, for near-white specimens, it is often useful to calculate a singular scale of yellowness or whiteness. This practice provides recommended equations for this scale and discusses their derivation and use, as well as the limits of their applicability (see also References (1) 2).
1.3 I valori espressi in unità SI sono trattati come valori standard. Nessun'altra unità di misura è inclusa in questo standard.
Calcolo dell'indice di giallo e dell'indice di bianco utilizzando coordinate di colore strumentali
1.4 Questo standard non è destinato a rivolgersi a tutti, se presente, problemi di sicurezza associati al suo utilizzo. È responsabilità degli utenti di questo standard stabilire una sicurezza adeguata, pratiche sanitarie e ambientali e per determinare l'applicabilità delle restrizioni normative prima dell'uso.
1.5 Questo standard internazionale si basa sui principi di standardizzazione riconosciuti a livello internazionale stabiliti nella Decisione sui principi per lo sviluppo di standard internazionali, Linee guida e raccomandazioni emesse dal comitato dell'OMC sugli ostacoli tecnici al commercio.