Rectified tiles are carefully reworked to size. Because they are calibrated, all long and short sides are cut to a uniform size. After rectification, all of the tiles are remeasured. There upon products that evidence curvature or a deviation in size are sorted out. This finishing process offers two advantages: Thanks to the exact form, rectified tiles can be installed with nearly invisible joints and all tiles are delivered with the same calibre. This means that it is no problem to offer combinations of various colours and series.