GB/T 2679.1-2020 "Paper - Determination of transparency - Diffuse reflectance method" applies to white and near-white translucent paper. For paper containing fluorescent whitening agents, an ultraviolet cut-off filter must be used to eliminate fluorescence excitation. The diffuse reflectance method is employed, using a reflectometer to measure the luminance factor of the sample backed by a black cylinder and a white backing, respectively. Transparency is then calculated according to the specified formula. The standard specifies instrument specifications, sample handling and testing procedures, and standardizes the presentation of results.
This summary is not the original standard text and is for reference only. For accurate information, please obtain it through official channels.
| Status | Active | ||
|---|---|---|---|
| CCS | Y30 | ICS | 85.010 |
| Release Date | 2020-07-21 00:00:00 | Implementation Date | 2021-02-01 00:00:00 |