GB/T 40277-2021 (English Version) PDF

Scope: This standard specifies the method for measuring the blue light diffuse reflection factor (ISO brightness) of paper, cardboard and pulp under indoor daylight conditions. This standard applies to white and nearly white paper, cardboard and pulp. When testing samples containing fluorescent whitening agents, the test can only be carried out after using a fluorescence reference standard to adjust the ultraviolet (UV) radiation energy level of the instrument to be consistent with CIE illuminant C. C light source has a certain proportion of UV content that is equivalent to indoor daylight conditions. Note: D65 brightness is tested by adjusting the instrument to comply with the CIE standard illuminant D65, which has a much higher UV content than specified in this standard. The test method standard for D65 brightness is GB/T7974.

GB/T 40277-2021 Referenced Document

GB/T 10739 Standard atmospheric conditions for handling and testing of paper, paperboard and pulp specimens*， 2023-12-28 Update
GB/T 450 Paper and board.Sampling for testing and identification of machine and cross direction,wire side and felt side
GB/T 740 Pulps-Sampling for testing
GB/T 8940.2 Pulp-Preparation of laboratory sheets for the measurement of brightness
ISO 2469 Paper, board and pulps*， 2024-03-01 Update
ISO 4094 Paper, board and pulps - General requirements for the competence of laboratories authorized for the issue of optical reference transfer standards of level 3

2021 GB/T 40277-2021 Paper, board and pulps—Measurement of diffuse blue reflectance factor( ISO brightness)—Indoor daylight conditions