Color Printing Quality Control Technology

In some traditional printing methods, the generally consistent printing plants have a drum scanner that performs characterization corrections based on the printing equipment at his rear end, and then uses some color control inverted tables as a tool to modify his characterization curves. A circular color monitor program. (Left photo is Mr. Zou Yukai)

When we are doing color monitoring program, we can use some guides to match the visual judgment of the human eye as a reference to correct some color deviations. However, because Taiwan still does not have a set of quality control standards that are more just than fair standards, there is no set of reference standards for printing practitioners.

We see from the continuous and growing trend of printing equipment in the United States since the 1990s that the total demand for printing equipment has been maintained at more than US$400 million by the year 2000. This represents a growing demand for printing equipment, and another digital printing machine ( More than 24 pages of printing per minute also showed a trend of growth.

Most people think that if a color is not really seen, then it cannot be identified as a color. It must be believed by seeing what it is. But can people's eyes really believe it? The human eye judges that color is based on one or more +R, G, or B sensing cells in the eye, but in a dimly lit environment, this single cell cannot function normally, and often produces unexpected colors. error. In the printing factory, the printing master often uses his own eyes to judge a special color formula. He thinks that the color is similar to printing directly on the machine. This method has many disadvantages:

1. Wasting time

2. The difference between the color and the actual color in the dark environment

3. Wasting money

People's eyes often cause errors in the judgment of the eyes because of the influence of some surrounding environment. Therefore, we must use some tools of quality control to assist us in judging colors and establish standards for quality control.

In terms of color communication, each country has a color system that they have developed, such as Munsell's color system in the United States, Ostwald in Germany, and Japan's color research system, which have caused color communication difficulties due to different standards in different countries. In the naming of colors, it is necessary to unify them. The color matching also needs attention, and it needs a coordination and consistency.

In addition to the commonly used densitometers and colorimeters in the human eye's auxiliary quality control tool, there is also a spectrophotometer that can measure the characteristics of luminous objects. He can calibrate the screen, or measure the standard color wheel, etc. inside it. There is a laser ball, he can take the spectral curve of the color ticket, but because of its higher selling price, it is less suitable for use by Taiwanese printing plants.

The use of digital cameras is becoming more and more common. However, due to the individual differences of each digital camera, in order to correct each digital camera, scientists use "digital swatches" to create a dedicated profile for digital cameras, correct the camera and Differences in human eye RGB signals.

After the screen is calibrated and characterized, an ICC profile can also be generated, but there must be a prerequisite that you must have a colorimeter as a quality control tool to assist the human eye. When we do screen color comparison, we must reduce the impact of surrounding light sources, turn off all light sources, and make adjustments in a completely dark environment to avoid affecting the accuracy of screen correction. The prevalence of the Internet has caused people to be different. In order to achieve such a goal, the remote screen must be calibrated to the same realm in order to achieve the purpose of CMS color management.

The copy-copy theory has the differences of concentration and colorimetry. Most people in color management only pay attention to the theory of colorimetry, but concentration is fundamental.

Digital workflow is a new method for printing companies to increase their production capacity. Printing companies can only improve their competitiveness if they work hard on digital production processes.

The application of quality control tools is because the human eye is too subjective in judging the color, and it lacks an objective measurement standard. Therefore, it is necessary to use quality control tools as an aid to the human eye as a basis for judgment. Use quality control tools and do not trust too much. your eyes

In response to the prevalence of the Internet, all print production may become a process of watching on the screen, so printing soft proofing becomes very important, and screen correction is relatively necessary.