Analysis of Color Mark and Its Influencing Factors in Printing Process (I)

What is the color standard

The Color Printing Industry Association of America (GCA) defines the color standard as "a strip-like sample used to measure printed matter such as dot gain, density, ghosting, double shadowing, contrast, and overprinting." Color patches are also often referred to as color guides or color control strips. It defines in a broad sense the performance of the color scale to measure and control color during the entire printing process from platemaking to print production.

Why not use the color scale instead of directly measuring the image itself?
Human eyes can feel 1,000,000 colors, but for most observers only about 20,000 of them can be distinguished. The printing colors (cyan, magenta, yellow, black) can reproduce approximately 4,000 colors. Although these densitometers or colorimeters can be used to measure the 4,000 colors, the measurement process is cumbersome and the cost is high. With the color mark, the operator can only measure some representative samples on the color mark, such as ink density, overprint density, etc. Based on these data, the operator can better understand the color reproduction problems that may occur during the printing process. .

The principle of color scale measurement:
--- All colors are generated by the interaction of incident light, paper, and the four printing primaries. Using the color mark, the operator can measure the light absorption characteristics of the four-color ink after printing, and then control the hue of the various colors produced by the four-color ink and its overprinting.

——————————————————————————————————————————————————————————————————————————————————————————————————— They were formed by the solid green-overprinting of solid magenta, solid-solid overprinting of solid yellow, and the solid product being overprinted with solid yellow. The overprinting efficiency of the latter ink adsorbed on the previous ink provides a basis for judging the overprinting degree of the ink on the entire image.

—————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————————- Knowing the transparent halftone dot values ​​and the ink and paper density of these areas can provide tonal reproduction information for the entire printing process. This process includes printers, inks, paper, operators, plates, blankets, and other factors.

By measuring and analyzing these defined few color patches, ghosting, gray balance and other characteristics can be marked so that the operator can understand and control the entire printing process in a most effective way. And printing process.

In addition to measuring the efficiency of ink transfer, the color scale can also perform color measurements. The area measured and calculated by the operator when controlling the printer is a solid or 25%, 50% or 75% area of ​​known colorimetric value. Measuring the hue value of the printed image itself is not the best way to analyze the reproduction performance of the print, because the hue value in the image itself is only for expressing the content of the image, and it varies with the image. The tone values ​​contained in the color scale can provide a consistent reference tone dot value at any time, regardless of the printed image.

The control of the printing process is to maintain the hue value on the film in accordance with the corresponding value transferred to the paper, which is a time-consuming and futile task for a printer operator operating at speeds of 1,000 to 2,000 inches per minute; The color scale will process this process, unless the color label film itself has a problem, otherwise it can indicate the problem by several color points.

What if the customer does not purchase a color mark?
Some production staff may feel that the color scales do not have so many benefits, and use this as a reason why they do not buy color scales. Customers who want a stable color quality must have a color mark because it is an essential tool for quality control. Operators and managers need to change the process in order to obtain consistent data in proofing and printing, while the color scales provide measurement tools and objects for the measurement process. The color scale can provide accurate and concise color blocks for measurement, and monitor printing, proofing, plate making and other printing production processes. The wideband densitometer is suitable for calibration, comparing target values ​​with reference values ​​and exchanging information with color standard elements.

Color Markers, Paper Waste, and the Environment Some printers and customers disregard the use of color patches and think that paper color patches will be wasted on paper. Although this statement has some correctness, the use of color marks can make the production quality more stable and more efficient. Because at this time prepress preparation and ink replacement are based on objective measurements, not subjective estimates. Even if the artistic director feels that the color is OK, the printing operator can use the color scale to make the printing condition and effect match the instruction as much as possible.

In fact, the analysis of many printed waste pages shows that the large amount of waste of paper is not due to the alignment of the color labels, but due to the incompatibility of the printed colors. Because the color scales have measurement and control functions, the investment in color scale trimming is much less than the time and material spent on waste pages.