Details:
Summary:
In 2020, Agfa introduced SPIR@L screening, an innovative technology with major advantages over conventional and other more modern screening technologies. Like its predecessor, Sublima™, SPIR@L screening is an XM screening that allows for highlights and shadows to be reproduced to their full extent.
As in conventional screening, darker tones are created by enlarging the small highlight dots into larger AM dots. However, contrary to the conventional ways, the small highlight dots are now enlarged in the form of a spiral instead of a round dot. The spiral curve has a certain thickness, which we call the ‘curve’. The pitch defines the clear space between two windings. This space is called ‘groove’. To produce the best output for a particular combination of printing process, ink, and paper, it is possible to adjust the curve and groove dimensions, giving this technology a very large latitude. The relation between these two parameters is key to press stability. By making the AM dot grow as a spiral, fine details in the mid-tones are rendered with more contrast. The lattice of the screen, however, is less visible.
Last but not least, by using this technology, less ink is needed to get the same density, as the ink is spread more efficiently. Consequently, a significant amount of ink is saved – with an average of 9.1% for the evaluated cases.
This paper contains a technical description of how the screen is built as well as some figures of the tests we have done. Currently, SPIR@L has been installed and shown to be operational for commercial heatset, commercial sheetfed, newspaper, and offset packaging. More than 100 split runs have been performed and have proven that SPIR@L does indeed account for significant ink-saving.