Kahulugan at Layunin
5.1 The original CIE color scale based on the three stimulus values X, Y, Z and chromaticity coordinates x, y is not visually uniform. Each subsequent color scale based on CIE values applies a weighting factor to provide a degree of uniformity so that the color differences across regions of the color space will be more comparable. Sa kabilang banda naman, it is unlikely that the same color differences obtained for the same samples evaluated in different color scale systems. To avoid confusion, comparisons should be made only when color differences or associated tolerances between samples are obtained for the same color scale system. For all colors of the specimen, there is no simple factor that can be used to precisely convert the color difference or color tolerance in one system into units of difference or tolerance in another system.

5.2 Color Difference E00 in Δ is highly recommended to use units (6) E* blood group units in the range of 0.0 to 5.0Δ. This color difference equation is applicable and widely used in industrial and commercial applications, including but not limited to automotive, mga patong na patong, mga pampaganda, mga tinta, packaging, mga pintura, mga plastik na, paglilimbag, security and textiles.

5.3 Users of the color tolerance equation have found the addition of the three vector color difference components into a single scalar value in each system to be very useful in determining whether the sample color is within the tolerance specified by the standard. Gayunpaman, in order to control for color in production, it may be necessary to know not only the magnitude of the deviation from the standard, but also the direction of this deviation. Information about the direction of small color differences can be included by listing the components determined by the three instruments for color differences.

5.4 Color tolerance selection based on instrument values should be carefully related to a visual assessment of the acceptability of hue, brightness and saturation differences obtained using practice D1729. The three tolerance equations presented here have been extensively tested against such data for textiles and plastics, and have been shown to be consistent with visual assessments, within the experimental uncertainty of visual judgments. This means that the equation itself misclassifies color differences whose frequencies are no greater than those of very experienced visual color matchers.

5.5 Although color difference and color tolerance equations are commonly applied to a variety of light sources, they have been derived or optimized, o pareho, for daylight illumination. A good correlation with visual judgment may not be obtained when calculations are performed using other light sources. The use of tolerance equations in conditions other than daylight conditions requires visual confirmation of homochromic levels according to practice D4086.

ASTM 2244-2022 “Calculation of Color Allowable Limits and Color Differences Using Instrumental Color Coordinates”

Saklaw ng
1.1 This practice includes the calculation of color tolerances and small color differences between opaque specimens, such as painted panels, plastic patches or textile samples, based on color coordinates measured by an instrument based on daylight illumination. Practice D4086 should be used to verify instrumental results if it is suspected that specimens may be metamorphic, na ang ibig sabihin ay, have different spectral curves despite visually similar colors. The tolerances and differences determined by these procedures are expressed in CIE 1976 CIELAB manual color space (1), 2 CMC tolerance units (2), CIE94 tolerance units (3), DIN99o color difference formula given in DIN 6176 (4), or approximately uniform visual color vision in CIEDE2000 color difference units (5).

1.2 For the Product specifications, the Buyer and the Seller shall agree on the allowable color tolerance between the specimen and the reference and the procedure for calculating the color tolerance. Specific color tolerances may be required for each material and use condition, as other appearance factors (e.g., sample proximity, gloss, and texture) may affect the correlation between the size of the measured color difference and its commercial acceptability.

1.3 Ang pamantayang ito ay hindi nilayon upang matugunan ang lahat ng mga isyu sa kaligtasan, kung meron man, na nauugnay sa paggamit nito. Responsibilidad ng gumagamit ng pamantayang ito na magtatag ng angkop na kaligtasan, mga kasanayan sa kalusugan at kapaligiran at upang matukoy ang pagiging angkop ng mga paghihigpit sa regulasyon bago gamitin.

1.4 Ang internasyonal na Pamantayang ito ay binuo alinsunod sa mga internasyonal na kinikilalang prinsipyo ng standardisasyon na itinatag sa Desisyon sa mga Prinsipyo para sa Pag unlad ng Internasyonal na Pamantayan, Mga Patnubay at Rekomendasyon na inilabas ng Komite sa mga Teknikal na Hadlang sa Kalakalan ng World Trade Organization.