'Exorcise' Ghosting From Your Print Process

Ghosting of the printed page is a phenomenon that plagues many printers. Quite simply, ghosting occurs when during the printing process elements other than the desired positive or negative ones duplicate themselves onto the printed surface.

These 'stencils' or 'ghost images' emerge from repeated passes of the ink form roller over the plate cylinder, and from a reduction or accumulation of ink.

One common cause of ghosting is the use of used (hard) or poorly adjusted ink-rollers. Another cause is weak pigmented inks.

An optimal balance between ink and dampening solution helps prevent ghosting, since too much water negatively influences printing outcomes.

Remedy

• When maintaining rollers, only use the appropriate cleansing agents; a weekly application of wash paste removes lime deposits, and will regenerate the rollers
• Adjust the rollers in accordance with the instruction manual; inspect the adjustment regularly
• Change used rollers: the rubber surface of older rollers will become glossy and over-smooth. At the same time, as their hardness increases, the edges bulge out in a trumpet shape. More pronounced abrasion becomes evident
• Adjust for maximum lateral reciprocation
• Adjust reciprocation of the ink form rollers
• Shift the engaging point of the lateral reciprocation
• Reduce the quantity of dampening solution being used (smearing limit)
• Employ high pigment inks
• Turn on the vario
• Turn the printing form (prepress)