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Standard Test Method for Visual Evaluation of Gloss Differences Between Surfaces of Similar Appearance
Automaticky přeložený název:
Standardní zkušební metoda pro vizuální hodnocení Lesk Rozdíly mezi plochami podobného vzhledu
NORMA vydána dne 1.12.2008
Označení normy: ASTM D4449-08
Poznámka: NEPLATNÁ
Datum vydání normy: 1.12.2008
Kód zboží: NS-27262
Počet stran: 6
Přibližná hmotnost: 18 g (0.04 liber)
Země: Americká technická norma
Kategorie: Technické normy ASTM
Keywords:
distinctness of image, gloss, haze, visual gloss, Reflectance and reflectivity--paints/related coatings/materials, Surface analysis--paints/related coatings/materials, Visual examination--paints/related coatings/materials, Absorption, Angle of incidence, Directionality of surface, Gloss, Hunter appearance, Light transmission and reflection, Photometry, Refractive index, Texture, ICS Number Code 87.040 (Paints and varnishes)
Significance and Use | ||||
Gloss is associated with the capacity of a surface to reflect more light in some directions than in others. The directions associated with mirror (or specular) reflection normally have the highest reflectances. Gloss is best seen and analyzed when the surfaces studied are illuminated by a light source that provides strong contrasting patterns of light and dark. Such a light source is described in this test method. The simplest concept of gloss is that it corresponds to the mirror-like reflectances of surfaces. However, the distributions and intensities of this surface-reflected light are (for real materials) highly variable and affected by a variety of factors: surface smoothness and contour, refractive index, absorptance, angle of incidence, and (to a generally small extent) wavelength. From the great variety of surface-reflection patterns met in materials of commerce, it has been possible to identify seven surface-reflection criteria or “types of gloss” regularly used by skilled technologists for intercomparing and rating their products for gloss. Six of the seven criteria, or “types of gloss,” are identified in the section on definitions. The seventh, luster or contrast gloss, is seldom of concern to the coatings industry. |
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1. Scope | ||||
1.1 This test method covers the visual evaluation of gloss differences of coating surfaces, using special types of lamps for illumination. It identifies six aspects or types of gloss that one may look for when using the lamp to assess gloss differences between surfaces. It describes the conditions for using the lamps to best identify small differences in each of the six types of gloss. Four levels of visual gloss differences are distinguished. 1.2 While this technique is useful for both weathered and unweathered specimens, it has not been applied to metallics. 1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of whoever uses this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. |
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2. Referenced Documents | ||||
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