Many printers who use UV inks and print onto synthetic substrates like CDs/ DVDs, ceramic tiles or coated papers
must repeatedly ask themselves how moiré problems can arise with full-colour printing. Why is it that large-format 4-colour raster Y+M+C+K prints perfectly, while other areas printed on the same pass that contain just two process colours, e.g. Cyan+Magenta, show a moiré pattern? What causes the subtle wave-like artefacts in Pantone colours printed onto CDs and DVDs ?

What is the cause ?

To minimise the deposit with UV inks requires fabric with 140 threads/cm or finer. When choosing a fabric, there is not only the thread count to consider, but also the thread diameter:
27, 31 or 34 microns. These variables produce differing mesh geometries, the critical factor being whether the mesh opening is greater than, equal to, or smaller than the thread diameter.
a) Mesh opening greater than thread diameter Very high resolution: finest lines and screens.
b) Mesh opening equal to thread diameter Good resolution and service life: a compromise between a) + c)
c) Mesh opening smaller than thread diameter

Very long service life and lowest possible ink consumption: used in large-format, with coarse rasters. It is mainly with fabrics of the type shown in c) that the fabric structure is visible with both colours a phenomenon that can however only been seen under the microscope. (Solvent-basedinks are less prone to this effect.)