In the prepress workflow, there are many factors for change. Therefore, the workflow process must be controlled to ensure that the printed product is accepted. With the improvement of electronic publishing, color evaluation has gradually approached the creative stage, and color management systems and color proofs have become indispensable prepress workflow tools. Color management systems are often used to produce predictable color matching between a device and another device. Color proofs (digital or analog, prepress proofs, or similar proofs) are key tools for monitoring every aspect of the image reproduction process. Using proofs, users, designers, color separation personnel, and printers can use it to judge the effect of the copy of a job.
In the early stages of scanning and color separation, proofs were the means of handling manuscripts using additional tools and adjustments, and they were also part of the job. As the job progresses, the control tools (foot scales, indicators, and color control bars) become necessary accessories to verify color stability and accuracy. Finally, the role of the proofs is the customer's request for the final imprint to accurately simulate the contract. The most useful place is that proofs must be made according to the characteristics of the printing process, such as color, density, dot gain, and image resolution. Properly made proofs are used by the print operator to guide the control of the printing (ink level, color balance, and print quality) so that the prints match the proofs provided. Once colors are recognized, what the customer expects is that throughout the printing process, features such as hue, color density, color balance, and dot gain remain stable.
* Color Management
How often have you or your users complained about the mismatch between printing proofs and matching sheets, or the problem of different printing jobs and screen displays? As our industry changes from analog to digital, the issue of color reproduction has become critical. We need to use color management to ensure better, faster and cheaper creation of color images because the process of creating images does not always achieve this effect. In addition, many images are now reused or reused in various media (for example, web images displayed on a computer screen or a computer on a CD-ROM), and it is often desired that these images be matched with printing effects. .
* Color gamut
The most basic problem of color matching comes from how color images are copied. No printing device or color display can replicate all the colors that human eyes can feel. The unique color range that each device can produce or display is called the device's color space. Some devices have a large color space, while others have limited color space. The color space of different systems can overlap but do not match.
Imagine the following example, if we want to print a copy of the color of the pink sweater, and at the same time hope that it can be displayed on the display through the website. The actual color may exist in the color gamut of the transmissive film, but may fall outside the offset gamut of the offset, and may also be outside the screen color gamut, not to mention the proofing device for predicting the color during the process. The color gamut is. In this case, the image of the pink sweater must be converted before output according to the output device (printer or computer screen) to best match the image of the original. The digital color management system has been further improved to achieve the purpose of color conversion in the production copying process.
* Color Management System
Color management is how to control and describe what we see on a computer screen, what the scanner captures, the color samples, and the image colors printed by the printer. From image creation or color capture to final image output, performing color conversion is done in a systematic manner. In the process of converting from one device to another (whether from a computer to a printer, or from a proof to a printer), the color management system maintains and optimizes the fidelity of color as much as possible.
The color management system is generally divided into three parts: calibration, characterization (device profile file), conversion (color gamut correspondence). Calibration is the method of adjusting each device (display, scanner, printer, etc.) to a defined standard state to ensure that it meets or is accurate to the manufacturer's specifications. Because the device changes at any time, this affects the way colors are displayed and generated, so the calibration process is very important. The calibration, or characterization process, is a description of the color gamut of each output device, producing the effect of identifying the colorant and the mode of operation. Profile files for these devices are often used in the conversion from one device to another. The transfer function draws the color of one device to another device, and must change so that both devices display or produce similar colors. Creating a user's profile file is not only important for every device, but it is also important for every type of paper used.
Article Source: PACK.CN
