The details of how HunterLab sphere instruments conform to ASTM D1003 Section 8: Procedure B Spectrophotometer for transmission haze measurement

HunterLab sphere instruments with CIE d/8 geometries conform to the requirements of ASTM D1003 Section 8: Procedure B Spectrophotometer. The measurement of transmission haze using Procedure B instruments will be in close agreement with ASTM D1003 Procedure A Haze meter.

Meeting ASTM D1003 Section 8 Procedure B Requirements

Here is a more detailed description of how the HunterLab UltraScan PRO and UltraScan VIS meet the requirements of Section 8.

1. Procedure B (Spectrophotometer)

8.1 Apparatus:

8.1.1 The instruments used for measurement shall meet the geometric and spectral requirement of this section.

HunterLab UltraScan VIS and UltraScan PRO instruments meet ASTM D1003 Section 8 Procedure B Spectrophotometer requirements.

8.1.2 The instrument shall be capable of computing from the spectral data the 1931 CIE tristimulus values and related color coordinates for CIE standard Illuminant C or alternatively Illuminant A.

HunterLab offers A/2 and C/2 options for calculating Haze%, Y Total and Y Diffuse luminous transmission in EasyMatch QC software.

8.1.3 The instrument shall utilize a hemispherical optical measuring system, with an integrating sphere, in which the specimen can be placed flush against the sphere port. The surfaces of the interior of the integrating sphere, baffles, and reflectance standards shall be matte, of substantially equal reflectance and highly reflecting throughout the visible wavelengths.

HunterLab UltraScan VIS and UltraScan PRO sensors and internal components are coated with Spectralon having a 99%+ reflectance. Transparent specimens for haze measurement are placed at the TTRAN port, flush against the sphere.

The UltraScan VIS and Pro come with white, Japanese commercial opal reflectance standard of 99%+ reflectance.

8.1.4 Two geometries can be used: unidirectional illumination with diffuse viewing and diffuse illumination with unidirectional viewing. Using diffuse illumination with unidirectional viewing, the following apply:

HunterLab UltraScan VIS and UltraScan PRO sensors have a diffuse illumination with unidirectional viewing (8°) geometry. They are referred to as CIE-conforming diffuse d/8° sphere instruments.

8.1.4.1 Use an integrating sphere to illuminate the specimen diffusely; the sphere may be of any diameter as long as the total port areas do not exceed 4.0 % of the internal reflecting area of the sphere. The specimen and light trap ports of the sphere shall be centered on the same great circle of the sphere, and there shall be at least 2.97 rad (170°) of arc between their centers.

The light trap port shall subtend an angle of 0.14 rad (8°) at the center of the specimen port along the wowing beam. With the light trap in position, without specimen the axis of the viewing beam shall pass through the centers of the specimen and light trap ports.

As scattering is dependent on all elements in the optical path, particularly the integrating sphere, these parameters must be defined. The HunterLab UltraScan VIS and UltraScan PRO sensors meet these sphere requirements.

8.1.4.2 View the specimen along an axis defined by a substantially unidirectional beam; the maximum angle that any ray of this beam may make with the beam axis shall not exceed 0.05 rad (3°). This beam shall not be vignetted at either port of the sphere.

The collection beam of HunterLab sphere sensors is near-collimated and meets these requirements.

8.1.4.3 When the specimen is in place, the angle between the specimen normal and the line connecting the centers of the specimen and the light trap ports shall not exceed 0.14 rad (8°).

8.1.4.4 With no specimen in place, the viewed area at the exit port shall be approximately circular, sharply defined concentric within the light trap port, leaving an annulus of 0.023 +/- 0.002 rad (1.3 +/- 0.01°) subtended at the specimen port.

NOTE 6—Note 3 and Note 4 apply. It should be noted that it may be difficult, but is critical, to meet this requirement.

The HunterLab UltraScan VIS and UltraScan PRO sensors meet these requirements.

8.1.5 A light trap shall be provided that will completely absorb the beam when no specimen is present, or the instrument design shall obviate the need for a light trap.

The light trap shipped with HunterLab UltraScan VIS and UltraScan PRO sensors meet this requirement.

8.1.6 A schematic drawing of a spectrophotometer with unidirectional illumination and diffuse viewing is shown in Fig. 2.

NOTE 7—It is strongly recommended that conformance to the intent of this test method be confirmed through use of properly calibrated haze standards due to the difficulty of confirming conformance to this test method when using a drill spectrophotometer.

Our colorimetric Procedure B spectrophotometers and the Procedure A Haze Meter both have similar sphere geometries but are not identical in construction. As stated in ASTM D1003, Procedure B- conforming instruments such as HunterLab ColorQuest XE, UltraScan VIS and UltraScan PRO d/8° sphere instruments, will agree closely with the Procedure A Hazemeter at the low near clear end (near 0), to a gradual bias of 2.5 units at the upper level of the method where Haze% = 30 as described in ASTM D1003 Table 4.

Here are typical Haze% measurement results reading a range of haze standards calibrated using a Procedure A Haze meter. They are in keeping with Table 4 performance.

8.2 Procedure—Follow the manufacturer’s instructions for the measurement of haze, and if none available, use Section 8.

HunterLab’s EasyMatch QC software prompts the user through the standardization and the two-step haze measurement procedure.

8.3 Calculation—Most spectrophotometers are computer driven and values for luminous transmission and haze are automatically calculated. If values are not computed use calculation method in Section 9.

HunterLab’s EasyMatch QC software calculates and reports Haze%, Y Total and Y Diffuse luminous transmission automatically.

8.4 Report:

8.4.1 Report the following data:

8.4.1.1 Source and identity of specimen,

8.4.1.2 Nominal thickness of specimen to the nearest 0.0025 mm or better for specimens less than 0.25 mm in thickness and to the nearest 0.025 mm or better for specimens greater than 0.25 mm in thickness.

8.4.1.3 Percent haze, to the nearest 0.1 % (indicate the average when reporting average values),

8.4.1.4 Total luminous transmittance, Tt, to the nearest 0.1 % (indicate the average when reporting average values and specify whether CIE Illuminant C or A is used) when specifically requested, and

8.4.1.5 Diffuse luminous transmittance, Td, to the nearest 0.1 % (indicate the average when reporting average values) when specifically requested.

HunterLab’s EasyMatch QC software prompts the user through the standardization and the two-step haze measurement procedure, as well as the averaging of multiple readings. Typically EZMQC reports Haze%, Y Total and Y Diffuse luminous transmission for A/2 or C/2 illuminant/observer conditions to two decimal places. This can be user-configurable to the nearest 0.1%.

8.5 Precision and Bias:

8.5.1 Precision:

8.5.1.1 Precision data in Table 4 is based on a round robin conducted in 1991 involving eight materials and seven laboratories.

For comparison purposes the same materials were measured on six regular hazemeters during the same round robin. The data from the regular hazemeter round robin is included in Table 3. (Warning—The following explanations of r and R (8.5.1.2-8.5.1.6) are intended to present only a meaningful way of considering the approximate precision of this test method. The data in Tables 1-4 should not be applied rigorously to acceptance or rejection of material, as those data are specific to the round robin and may not be representative of other lots, conditions, materials, or laboratories. Users of this test method should apply the principles outlined in Practice E691 to generate data specific to their laboratory and materials, or between specific laboratories. The principles of 8.5.1.2- 8.5.1.6 would then be valid for such data.)

8.5.1.2 For the purpose of compiling summary statistics, a test result has been defined to be the average of three replicate measurements of a property for a material in a laboratory, as specified in this test method. Summary statistics are given in Table 4. In each table, for the material indicated, S(r) is the pooled within-laboratory standard deviation of a test result, S(R) is the between-laboratory standard deviation of a test result, r = 2.83 3 S(r) (see 8.5.1.3), and R = 2.83 3 S(R) (see 8.5.1.4).

8.5.1.3 Repeatability—In comparing two mean values of the same material, obtained by the same operator using the same equipment on the same day, the means should be judged not equivalent if they differ by more than the r value for that material.

8.5.1.4 Reproducibility—In comparing two mean values for the same material obtained by different operators using different equipment on different days, either in the same laboratory or in different laboratories, the means should be judged not equivalent if they differ by more than the R value for that material.

8.5.1.5 Judgments made as described in 8.5.1.3 and 8.5.1.4 will be correct in approximately 95 % of such comparisons.

8.5.1.6 For further information, see Practice E691.

8.5.2 Bias—Measurement biases cannot be determined since there are no accepted referee methods for determining these properties.

The HunterLab ColorQuest XE, UltraScan VIS and UltraScan PRO sensors meet the precision performance requirements of Section 8.5.