This part of GB/T 2679 specifies the method for measuring the transparency of paper by the diffuse reflectance method. This section applies to white and near-white translucent paper. To measure paper containing optical brighteners, use a UV-cut filter to eliminate fluorescence excitation. Note: Although GB/T 7973 allows the use of filter-type reflectance photometers and simple spectroreflectance photometers, if the filter-type reflectance photometer cannot eliminate the excitation of fluorescence, it is not suitable for testing paper containing fluorescent whitening agents. transparency.
GB/T 2679.1-2020 Referenced Document
GB/T 450 Paper and board.Sampling for testing and identification of machine and cross direction,wire side and felt side
GB/T 7973 Paper,board and pulps-Measurement of diffuse reflectance factor(Diff/ Geometry)
GB/T 2679.1-2020 history
2020GB/T 2679.1-2020 Paper—Determination of transmittance—Diffuse reflectance measurement
2013GB/T 2679.1-2013 Paper.Determination of transmittance.Diffuse reflectance measurement