Boxmeer, The Netherlands, February 2012: Stork Prints has introduced a new screen, called RandomScreen. The number of holes in this screen is comparable to a 125 mesh screen. Its hole size is 79 micron, like in a PentaScreen 125. The hole shape however, is more streamlined and the screen’s paste flow and delivery is slightly higher in comparison to a Penta 125 screen. The result is evident: a significantly improved printability.
The main benefit of the new RandomScreen is to surpress so called moiré effects. Moiré is an effect that occurs, when two regular structures interfere and thus a new, third pattern is created. This can happen when a screen’s regular mesh structure and a line raster’s grid structure meet. To avoid these moiré effects, the holes in a RandomScreen are not arranged on straight lines as is the case for conventional screens. The position of each hole is just slightly out of line and therefore there is no risk of raster's grid interference. Moiré occurs typically at certain grey values, where the size of raster dots is getting lower and the raster’s grid structure becomes more evident. In some areas of the screen the engraved dots are matching the screen holes and in others they are not. The moiré effect is typically visible as a diagonal striping pattern.
Another source of moiré can be the construction pattern of the textile. Some textiles like knitted goods, georgette or javanaise show a tendency for this effect. Also in this case the RandomScreen improves the printing results.
Looking in detail to the repetitive structures in a moiré area, one can find a pattern, sometimes described as a Rosette-pattern, where circles of raster dots are arranged around a center dot. This effect disturbs geometrical raster designs, e.g. when imaging a weaving or a bark structure. Using the new RandomSreen will avoid this.
The streamlined hole-shape of the new RM 125 screen leads to an improved and higher paste flow. This results in more contrast in raster areas, which leads to a more relief-like look in geometrical raster patterns.
The new RandomScreen is an interesting supplement to the range of Stork Prints mesh screens. It has the capability of solving engraving problems for geometrical raster designs and moiré effects in halftones.