On structural properties affecting the picking tendency of newsprints

The relationship between beta-formation and picking is assessed using advanced and objective image processing and analysis techniques. Local beta-formation and picking analyses were performed on the same samples before and after printing. The shape and dimensions of the picking areas are given detailed descriptions. Picking areas are mostly encountered on the surface of high basis weight areas (flocs). The transition areas between floes and anti-flocs (relatively low basis weight areas) have also a large picking tendency. However, taking into consideration the area fraction comprised by the floes and surroundings, it is clearly demonstrated that there is more picking in the floe areas compared to the surroundings and anti-floes. Specific formation in the wavelength range between approx. 8 and 16 mm explained 47% of the picking occurrence.