As can be seen in Figure 3, the initial brightness of each pulp differed significantly. Immediately noticeable is the es- pecially low brightness of pulps obtained from hemp stalks subjected to the retting process, i.e. hemp wood (Hw-r) and hemp bast fibres (Hbf3), of around 29%. The initial ISO brightness of the remaining pulps ranged from circa 38 to 50%, being the highest in the case of birch pulp. The pulp samples were initially subjected to bleaching with chlorine dioxide (sequence D0EPD1).