GB/T 2679.1-2020Paper--Determination of transmittance--Diffuse reflectance measurement (English PDF)

Foreword

GB/T 2679 is currently divided into the following parts:

- GB/T 2679.1 Paper - Determination of transmittance - Diffuse reflectance

measurement;

- GB/T 2679.2 Sheet materials - Determination of water vapour transmission rate -

Gravimetric (Dish) method;

- GB/T 2679.6 Corrugating medium - Determination of the flat crush resistance after

laboratory fluting;

- GB/T 2679.7 Board - Determination of puncture resistance;

- GB/T 2679.8 Paper and board - Determination of compressive strength (Ring crush

method);

- GB/T 2679.10 Paper and board - Compressive strength - Short span test;

- GB/T 2679.11 Paper and board - Qualitative analysis of mineral filler and mineral

coating - SEM/EDAX Method;

- GB/T 2679.12 Paper and board - Qualitative analysis of mineral filler and mineral

coating - Chemical method;

- GB/T 2679.14 Filter paper and filterboard - Determination of maximum pore

diameter;

- GB/T 2679.17 Corrugated fibreboard - Determination of edgewise crush resistance

(Edge reinforced method).

This Part is Part 1 of GB/T 2679.

This Part is drafted in accordance with the rules given in GB/T 1.1-2009.

This Part replaces GB/T 2679.1-2013 "Paper - Determination of transmittance - Diffuse

reflectance measurement". Compared with GB/T 2679.1-2013, the main technical

changes are as follows:

- Add the term "White backing luminance factor" (see 3.4);

- Delete "Transmittance" (see 3.4 of the 2013 edition);

- Change the definition of "Transmittance from reflectance factor measurements"

(see 3.5; 3.5 of the 2013 edition);

- Modify the "Filter-function" in the "Apparatus" (see 5.2; 5.2 of the 2013 edition);

- Modify the measurement accuracy of luminance factor in the test procedure (see

8.2, 8.3 and 8.4; 8.2, 8.3 and 8.4 of the 2013 edition);

- Modify the labeling of Ry and R0 in the calculation (see Clause 9; Clause 9 of the

2013 edition);

- Add the structural changes of this Part compared with ISO 22891:2013 (see Annex

A).

This Part uses the redraft law to modify and adopt ISO 22891:2013 "Paper -

Determination of transmittance by diffuse reflectance measurement".

Compared with ISO 22891:2013, this Part has more adjustments in structure. Annex A

lists the comparison of clause-subclause numbers between this Part and ISO

22891:2013.

The technical differences between this Part and ISO 22891:2013 and their reasons are

as follows:

- As for the normative references, this Part has made adjustments with technical

differences, to adapt to the technical conditions of China. The adjustments are

mainly reflected in Clause 2 "Normative references". The specific adjustments are

as follows:

 Replace ISO 186 with GB/T 450, which modifies and adopts the international

standard;

 Replace ISO 2469 with GB/T 7973, which is not equivalent to the international

standard;

 Delete reference to ASTM E308-06.

- Change the definition of the term "Luminance factor". Use "CIE standard

illuminant D65 and CIE 1964 supplementary standard chromaticity system" to

replace "CIE standard illuminant C and CIE 1931 standard chromaticity system in

ISO 22891:2013", to be consistent with the instruments and related standards for

measuring paper color in China's paper industry (see 3.2 and 5.2).

- Delete the terms "Intrinsic luminance factor", "Transmittance", "Regular

transmittance", "Diffuse reflectance transmittance", "Transparent medium", and

"Translucent medium", to meet the technical conditions of China.

- Replace the luminance factor (C), the single-sheet luminance factor (C) and the

white backing luminance factor (C) in the standard WITH the luminance factor

(D65), the single-sheet luminance factor (D65) and the white backing luminance

factor (D65) respectively; to be consistent with the technical conditions of test

instruments in China (see 3.2, 3.3, 3.4, 3.5, 8.2, 8.3, 8.4).

- Modify the provisions of filter reflectometer and abridged spectrophotometer, to

be consistent with the technical conditions of test instruments in China (see 5.2 and

Annex B).

- Add the requirement that "The Ry value of the backing is (84.0+/-1.0)%", to eliminate

the result deviation caused by the white backing (see 5.6).

- Modify the calculation formula in the calculation, to be consistent with the

technical conditions of test instruments in China (see Clause 9).

- Modify Annex A "Spectral characteristics of reflectometer for determining diffuse

reflectance factor" of ISO 22891:2013 (see Annex B).

- Delete Annex B, Annex C, and Bibliography of ISO 22891:2013. The content of

these parts is not suitable for China's national conditions.

This Part makes the following editorial change:

- Change the standard name.

Attention is drawn to the possibility that some of the elements of this document may be

the subject of patent rights. The issuing authority of this document shall not be held

responsible for identifying any or all such patent rights.

This Part was proposed by China National Light Industry Council.

This Part shall be under the jurisdiction of National Technical Committee 141 on Paper

Industry of Standardization Administration of China (SAC/TC 141).

Drafting organizations of this Part: Hangzhou Fuyang Institute of Measurement for

Quality and Technique Supervision, Zhejiang KAN Special Materials Co., Ltd.,

Minfeng Special Paper Co., Ltd., Zhejiang Hua Feng Paper Group Co., Ltd., Zhejiang

Xinfeng Special Paper Co., Ltd., Qingdao Jiaze Packaging Co., Ltd., China National

Pulp and Paper Research Institute Co., Ltd.

Main drafters of this Part: Wo Qizhong, Ge Jinlan, Chen Hua, Cheng Yimin, Zhou

Minghua, Li Dafang, Wang Qiuting, Wang Xiaoli, Bai Meiqiao, Zhang Zhilong.

The previous editions of the standard replaced by this Part were released as follows:

- GB 2679.1-1981, GB/T 2679.1-1993, GB/T 2679.1-2013.

Paper - Determination of transmittance - Diffuse reflectance

measurement

1 Scope

This Part of GB/T 2679 specifies the method for determination of transmittance by

diffuse reflectance measurement.

This Part applies to white and near-white translucent paper. To measure paper

containing fluorescent whitening agents, use a UV cut-off filter to eliminate

fluorescence excitation.

Note: Although GB/T 7973 allows the use of filter reflectometers and abridged spectrophotometers,

if the filter reflectometer cannot eliminate the excitation of fluorescence, it is not suitable for

testing the transmittance of paper containing fluorescent whitening agents.

2 Normative references

The following documents are indispensable for the application of this document. For

the dated references, only the editions with the dates indicated are applicable to this

document. For the undated references, the latest edition (including all the amendments)

are applicable to this document.

GB/T 450 Paper and board - Sampling for testing and identification of machine and

cross direction, wire side and felt side (GB/T 450-2008, ISO 186:2002, MOD)

GB/T 7973 Paper, board and pulps - Measurement of diffuse reflectance factor

(Diff/Geometry) (GB/T 7973-2003, ISO 2469:1994, NEQ)

3 Terms and definitions

The following terms and definitions apply to this document.

3.1

Reflectance factor

The ratio OF the radiant flux reflected by an object TO the radiant flux reflected by a

perfect reflecting diffuser under the same conditions.

5 Apparatus

1964 supplementary standard chromaticity system under the CIE standard illuminant

D65.

For an abridged spectrophotometer, the instrument shall be equipped with a 420 nm UV

cut-off filter. And according to the weighting coefficients in Annex B, the CIE 1964

supplementary standard chromaticity system tristimulus value Y10 of the tested sample

under the CIE standard illuminant D65 can be calculated.