Color vision and digital color equipment management points (below)

system error

Restore graphics and image data. Color devices must use their own color modes. Scanners, digital cameras, and color displays use the RGB mode. Color printers and printers use the CMYK mode. Host processing can use any mode. LAB mode is used for data exchange. These color modes are based on the International Commission on Illumination (CIE) standard. But the color range they describe is different. LAB is the complete set of color space with the largest range; RGB is the available screen display portion of LAB, followed by the range; CMYK is the printable portion of LAB with the smallest range. Therefore, systematic errors occur when data flows from a pattern with a large color range to a pattern with a smaller range. In addition, color devices use different bit depths when they are manufactured, resulting in output errors when data flows from an acquisition device with a high bit depth to an output device with a low bit depth.

Human error

Human error is often the main cause of data distortion. Many operators do not really understand color devices, and mistakenly use data exchange methods, image color modes, resolution, etc., which of course cause severe reproduction distortion.

5. Common color device management methods

"WYSIWYG" is the ultimate goal of color management. This goal is to achieve the same color between the acquisition device and the output device. Although color equipment manufacturers are all working hard to provide customers with more convenient and practical color management programs for their equipment, in essence these solutions do not solve color problems. The color problem is actually a system problem. In a complete color system, different color devices come from different manufacturers. What they need is an overall management plan. In order to achieve color management, these devices must first do the following:

Uniformity of bit depth

The bit depth used by different devices connected together must match each other. Bit depth is one of the most important hardware indicators of a color device. It directly affects the device's ability to express colors and overall performance. Devices with high bit depth can be compatible with data in devices with low bit depth, and vice versa. So in order for the color devices to work properly, they must use the same bit depth, which is the hardware basis for color management.

Uniform resolution of the target

When image data flows between different color devices, the resolution of its use is determined for the target device it flows. Different color reproduction devices use different resolutions to display graphics and images. For example, a color display will always use 72 dpi for display, and only 150 dpi for image printing can be used, while imagesetters use 350 dpi. Therefore, when using an acquisition device to obtain an image, its use should be considered first. For display, 72 dpi is sufficient; for printing, 150 dpi is sufficient; for printing, 350 dpi must be used. The higher the resolution is, the clearer the image output is, and the unsuitable resolution will only increase the data file, prolong the reproduction time, and sometimes even have a negative effect.

Uniform color model for the target

When image data flows between different color devices, the color mode used by the target device for which it flows is determined. Different output devices use different color modes, such as the monitor using the RGB mode, and the CMYK mode for color playing and photo-taking. When acquiring a device to obtain an image, a color mode is determined according to its purpose. For display only, the RGB mode is used, and the CMYK mode is used for color printing and print photoprinting. Unsuitable color modes can significantly affect image reproduction. For example, when the RGB mode image output is printed, the result is no longer colored but black and white.

Unified image format for the target

When image data flows between different color devices, the data storage format used by the target device for its flow is determined. Different storage formats have a great influence on the color of the image. For the network GIF format, the use of color index table storage, itself does not support true color can only use 256 colors; PIC, BMP, PCX support large size of the true color map are more reluctant; JPG format supports true color but due to compression And it's lost. Therefore, after using the acquisition device to obtain the image, the storage format used by the device should be determined according to its use. When it is used in a network (such as a web page), it is stored in a GIF format; in a PC, it is stored in a BMP format; when high-efficiency compression is needed, it is saved as a JPG. Format and so on. Of course, the commonly used format is the TIF format.

Process color calibration

Calibrate the same color in the different color devices when the error, so that color-induced. The specific process is to establish a system of color pre-profiling files (PROFILE) for the acquisition device and the output device respectively, and the color pre-production files are connected in series to calibrate the entire system.

More and more software and hardware have gone deep into the field of color management. Color devices are currently one of the fastest and most frequently updated computer external devices that receive advanced technology. As a color management system for managing color devices, it is bound to continue to develop in a more complex, more efficient, and more accurate direction.