At 15:41 12-11-2007 +0100, Lars Jacobsen wrote: Hi Lars, Those small wedges are great to check the plates during production. However, to control the jumps as described by Fogra, you need more sophisticated materials. I hope that you already applied the Altone Test Suite. On the prints you already can detect the tone jumps. In the Visual file 4 large round patches are used to check this. If you don't have the Altona yet, you can download the visual file free of charge. Several printers suggest their customers to download this file to check the basic quality of their proofing systems. This is one of the reasons to make just this Visual file free of charge. The other files, Measure and Technic, plus the digital and analog information is not free of charge but can be purchased via the www.altonetestsuite.com web site. The Fogra digital Plate test file has a lot of additional test patches to check your workflow. I would invest in both Altona and the Fogra Test for your CTP. The Four Colour check plot is a graph with the measurements of all four tonal curves. The long halftone wedges are used to measure that condition. One can see the shape of the individual curves and the relation between the 4 different shapes. If they bump at the same point, it seems a CTP problem. If they bump only in one colour, you have (most probably) a press problem. The round control patches can be used to check the influence of the print and plate direction. Lots of success, Henk