GB/T 1867-2008 provides a detailed specification for the reduction blue RSN (C.I. reduction blue 4). The standard specifies the technical indicators of the reduction blue RSN, including Appearance color, intensity, color light and dyeing performance in different media. It elaborates the sampling rules and inspection methods of the product, such as evaluating its dyeing effect through specific dyeing tests. This standard provides a unified mass measurement scale for the production, trade and application of the reduction blue RSN, which helps to ensure the mass of the product, meet the requirements of the printing and dyeing industry for the dyestuff in terms of color and fastness, and promote the orderly development of related industries.