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GB/T 2378-2025Acid dyes — Determination of shade and relative strength (English PDF)

酸性染料　色光和强度的测定

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Issued by

SAMR; SAC

Level / Type

National · Recommended

Issue date

August 29, 2025

Implementation date

March 1, 2026

Scope

GB/T 2378-2025 is the English-translated version of 酸性染料　色光和强度的测定.

GB/T 2378-2025 is the Chinese national standard covering comparing a batch of acid dye with the reference — the dyeing of wool or nylon under fixed conditions and the visual and instrumental comparison of shade, and the relative strength that decides how much of the batch is dosed. Issued on 29 August 2025, it has been in force since 1 March 2026, replacing GB/T 2378-2012.

Document preview — GB/T 2378-2025

National Standard of the People's Republic of China

ICS: 71.100.01
Classification: G 55
Replacing: GB/T 2378-2012

Issued by: State Administration for Market Regulation; Standardization Administration of the PRC

Foreword
1 Scope
2 Normative references
3 Terms and Definitions
4 Principles
4.1 Staining method
4.2 Solution colorimetry
5 Reagents and Materials
6 Instruments and Equipment

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for standardization work Part 1: Structure and drafting rules for standardization documents" Drafting.

This document replaces GB/T 2378-2012 “Acid dyes - Determination of color and strength” and GB/T 33421-2016 “Liquid Acid dyes - Determination of color and intensity. This document is based on GB/T 2378-2012 and integrates the content of GB/T 33421-2016.

Compared with GB/T 2378-2012, in addition to structural adjustments and editorial changes, the main technical changes are as follows.

a) The scope of application of this document has been changed (see Chapter 1, Chapter 1 of the 2012 edition);

b) Added a chapter on terms and definitions (see Chapter 3);

c) Added the principle and test method of solution colorimetry (see 4.2 and 7.2);

d) The dyebath formula for nylon dyeing has been changed (see 7.1.2.3, 6.2.3 of the 2012 edition).

Please note that some of the contents of this document may involve patents. The issuing organization of this document does not assume the responsibility for identifying patents.

This document was proposed by the China Petroleum and Chemical Industry Federation.

This document is under the jurisdiction of the National Technical Committee on Standardization of Dyes (SAC/TC134).

This document was drafted by: Jinhua Shuanghong Chemical Co., Ltd., Shenyang Shenyang Institute of Chemical Technology Testing Technology Co., Ltd., Shenyang Institute of Chemical Technology Co., Ltd.

Co., Ltd., Chuanhua Zhilian Co., Ltd., and Shenhua Testing Technology (Nantong) Co., Ltd.

The main drafters of this document are: Zheng Weiliang, Yang Zhenmei, Li Jingyi, Xu Liang, Zhao Ting, and Tao Shuaijiang.

The previous versions of this document and the documents it replaces are as follows.

— First issued as GB/T 2378-1980 in 1980, first revised in 2003, second revised in 2012;

— This is the third revision and incorporates the content of GB/T 33421-2016 “Liquid acid dyes - Determination of shade and intensity”.

1 Scope

This document describes methods for the determination of the shade and intensity of acid dyes by staining and solution colorimetry.

This document applies to the determination of the color and intensity of acid dyes. The dyeing method is applicable to acid dyes used to dye textiles.

The color method is suitable for acid dyes with higher purity or used in daily chemicals.

2 Normative references

GB/T 2374-2017

GB/T 6687

3 Terms and Definitions

The terms and definitions defined in GB/T 6687 apply to this document.

4 Principles

4.1 Staining method

Use the acid dye sample and the standard sample of the same type to dye on appropriate fibers (wool, nylon) under the same conditions.

Take the color intensity of the standard sample as 100 points and the color as the standard, and make a visual comparison to evaluate the color and intensity of the sample.

Measure the color and then calculate the color and intensity of the sample.

4.2 Solution colorimetry

When the dye solution complies with the Lambert-Beer law, the acid dye sample and the standard sample are diluted with water and measured with a spectrophotometer.

The intensity of the dye sample can be calculated by determining the absorbance value at the maximum absorption wavelength.

The color of the sample can be evaluated by comparing the color difference between the standard sample and the test sample.

5 Reagents and Materials

Reagents and materials should comply with the relevant provisions of Chapter 3 of GB/T 2374-2017.

6 Instruments and Equipment

Instruments and equipment should comply with the relevant provisions of Chapter 4 of GB/T 2374-2017.

......
This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 15 pages — is available in the English PDF.

Referenced standards

Normative references

Cited by

Editions of GB/T 2378

Edition	Title	Revision	Status
GB/T 2378-2025	Acid dyes - Determination of shade and relative strength	current edition	Current
GB/T 2378-2012	Acid dyes -- Determination of dyeing shade and relative strength	previous edition	In force
GB/T 2378-2003	Acid dyes -- Determination of dyeing shade and relative strength	previous edition	Obsolete
GB/T 2378-1980	Method for the determination of shade and colouring strength for acid dyes	previous edition	Obsolete

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