Quality defects and causes of printing products: 

Partial color: the reason may manuscript of poor quality, the plate is not accurate, print controlling conditions inconsistent, ink control step, look like the light source are not standard. 

Dark, not bright. The reason a manuscript of poor quality, poorly designed plate curve, low density separations), print is not real shallow imprinting, printing pressure is low, aging of printing machine, dampening liquid excess, rough paper, white degree is too low. 

Shampoo text: the reason may have positive density is low, film fog to a greater degree, print false imprinted too shallow, printing pressure is low, aging of printing machine, dampening liquid excess, the amount of ink is insufficient. 

Paste version: as a result of the printing plate part of the ink, resulting in the printing on the printing is not clear, is an offset printing. 

The dirty version: due to a printing plate wetted part bad, cause the blank part. 

Version: flat printing plate picture and text subtle tone becomes shallow, network and line area decreases, and even lose the affinity. 

Dot gain: the substrate area of the Internet than the corresponding part of the printing plate on the corresponding part of the dot area. 

Heap ink: ink or other materials are deposited on the roller or blanket to form embossed sediments, affect the ink blot transfer. 

Deinking: metal roller by wet oxidation and erosion of liquid ink rejection phenomenon. 

Ink emulsification: the phenomenon of ink absorption wetting liquid in printing process or the printing fault caused by excessive wetting liquid in ink. 

Nap: printing process, because the ink is too sticky or paper surface strength difference from the surface of the paper off or removed due to the paper fiber, filler and coating. 

Printing failure: a general term for the phenomenon that affects the normal production or the quality of the printed matter in the printing process. 

Misregister: in the color printing process, printing error trace overlap. 

Heavy shadow: the double outline of the same color dots, lines, or words on the printed matter. 

On the back of the stick dirty: printing ink printed on the substrate, stick on the back of another sheet, caused by dirty. 

Printed on the paper on the back visible.