at high speed. In some cases, electron beam lithography has been used instead. The curing of the ink was then initiated directly by an electron beam scanned across the surface. Defects Design defects Double images on the relief and in depth Double images are usually caused by an exaggeration of the 3D effect from some angles of view, or an insufficient number of frames. Poor design can lead to doubling, small jumps, or a fuzzy image, especially on objects in relief or in depth. For some visuals, where the foreground and background are fuzzy or shaded, this exaggeration can prove to be an advantage. In most cases, the detail and precision required do not allow this. Image ghosting Ghosting occurs due to poor treatment of the source images, and also due to transitions where demand for an effect goes beyond the limits and technical possibilities of the system. This causes some of the images to remain visible when they should disappear. These effects can depend on the lighting of the lenticular print. Prepress defects Synchronization of the print (master) with the pitch This effect is also known as "banding". Poor calibration of the material can cause the passage from one image to another to not be simultaneous over the entire print. The image transition progresses from one side of the print to the other, giving the impression of a veil or curtain crossing the visual. This phenomenon is felt less for the 3D effects, but is manifested by a jump of the transverse image. In some cases, the transition starts in several places and progresses from each starting point towards the next, giving the impression of several curtains crossing the visual, as described above. Discordant harmonics This phenomenon is unfortunately very common, and is explained either by incorrect calibration of the support or by incorrect parametrization of the prepress operations. It is manifested in particular by streaks that appear parallel to the lenticules during transitions from one visual to the other. Printing defects Color synchronization One of the main difficulties in lenticular printing is color synchronization. The causes are varied, they may come from a malleable material, incorrect printing conditions and adjustments, or again a dimensional differential of the engraving of the offset plates in each color. This poor marking is shown by doubling of the visual; a lack of clarity; a streak of color or wavy colors (especially for