Due to the fact it is top-class packaging printing, customers usually have very high expectations and may be even be called to the point of picky for the quality of the finished product. The quality control in this printing process is essential to completing these jobs well. But sometimes even under the most detailed operations, differences in coloration cannot be completely avoided, there might be variations in the degree of color differences. We will analyze and explain why differences in coloration may be present in high-grade envelop prints.

One of the possibilities for this phenomenon is due to the differences in a sampling machine and a printing machine. When printing top-class packaging, the sampling machine uses a flat printing method and the printing machine uses the rolling method. The sampling machines watering and inking system does not perform as well as the printing machine, so in the balancing of ink, netting, layering of different images the products from a sampling machine will be slightly different.