Büchner funnel prepares specimen sheets for reflectance testing of bleached or unbleached pulp whose fibers are readily dispersed in water.
Specimen sheets are made at pH of 6.5 ± 0.5.
TAPPI Standard Practice T 272 describes a procedure for using the sheet machine for making hand sheets for the application.
Reflectance testing on hand sheets prepared by this method can be performed using TAPPI T 452
“Brightness of Pulp, Paper, and Paperboard (Directional Reflectance at 457 nm),” or TAPPI T 525 “Diffuse Blue Reflectance Factor of Pulp (Diffuse Brightness).”
