Color Management

Color management, which is often hung on people's lips, actually refers only to the management of the transfer of color spaces (such as scanners, computer screens, printers, etc.); however, printers have always tried to practice color consistency and repeatability, or Stability management is not included in the current popular color management. It is important to note that the two are different. If you focus on only one side of the actual production process, it is difficult to control the quality and stability.

Both must be balanced
The CMS mentioned so far is only able to achieve visually similar and consistent results when colors appear in different media (spaces), but it cannot manage to maintain stable reproducibility when colors appear in the same space. . That is, after a picture is scanned and actually printed, its color effect can be the most similar, but it cannot guarantee that the second printed piece can be similar to the first one. Thus extending to the use of the same film at different times of printing, whether the printed products can be consistent, which involves the process control of the printing process (processcontrol), but no one realizes that this is actually the color management One part. From this point of view, even if the color space transfer management can be maintained properly, it ignores the management of color repeatability and consistency, and may not necessarily achieve the desired effect when printing. Therefore, the color control of practice should be equal to both.

Mr. Fang Junyang, an engineer at the Printing Materials Testing and Analysis Center of the Association, pointed out that the color space transfer management can learn from the system whether certain colors can be reproduced by printing, predicting the deviation from the final printing, and when the printer actually prints, the printing master can It is easier and quicker to make proper adjustments on the press. However, in the process of adjustment, the test prints should also be tested, that is, to record the instrument measurement data, so that we can know the true capabilities of the machine.

Factors other than density
For printers, the quality of prints is digitized and recorded. Each time the density of dots is considered, most people think that if they can control the density of dots, it means that other factors have been controlled.

It is no wonder that Miss Wang, an application engineer at GretagMacbeth, said with a smile that when people in the printing industry use their color measuring instruments, they often only use the function of measuring density.

However, in addition to the density, in addition to the density, the instrument measures the color of prints: 1 dot gain, and if the dot is larger, the density will increase; 2 the effect of color overlapping (trapping); 3 Hue error and contrast between colors. If you can master these data well, you can understand the characteristics of the printing process, thus improving the color stability of the printed matter.

How to communicate with color data
However, many people will encounter a question: The data measured by different color measurement instruments are different. Which data should be used? In fact, the color numbers measured by different color measuring instruments must be different. Therefore, when communicating with color data, several restrictions must be observed. First of all, the two sides need to use the same brand and model of color measurement instrument, in addition to measuring the same light source, even at the same temperature and humidity, etc., in order to affirm that the two sides can not go wrong. Therefore, it is more meaningful to use the same colorimeter to obtain the data.