Color Management-use different color schemes for different purposes

Recently, I plan to design a T-shirt program for the Guangzhou. NET Club, and once again encountered the problem of color management. Fortunately, after two days of study and experiment, I found some experiences.

Color Management is an important concept in the graphic processing software (Photoshop, Illustrator, etc.) produced by Adobe. Have you ever encountered the following problem: a good-looking figure on your monitor looks bad on other monitors? Or is the effect printed on the color printer far different from that on the display? If the answer is yes, you need to understand the concept of color management. The purpose of color management is to make the colors of the images you process on multiple devices (including multiple monitors, printers, and scanners) as consistent (or predictable) as possible ). How to manage colors? Look at help. I still don't understand it? The following uses Adobe Photoshop as an example to describe my understanding of color management.

The first step is to find and install the right drivers for a variety of devices, including scanners, monitors, and printers, this is because the color configuration file (ICC or ICM file) of the device is usually installed at the same time when the driver is installed ). This file is very important. various colors are correctly displayed on the corresponding device through its conversion. Therefore, if an incorrect device driver is installed, the incorrect color configuration file may be used. The consequence is, of course, the incorrect color. For the monitor, you can view the control panel → display → set options → click the Advanced button → whether the configuration file used in the color management options page matches your monitor. If your color management options page is blank, you may not have installed the driver, or you are using a base-grade display. You don't need to be discouraged. Even a general plug-and-play display can use software to generate a color configuration file. If Adobe's graphic processing software is installed, an Adobe Gamma software is installed on the Control Panel to generate a display color configuration file (Note: if you do not understand its description, don't get it. If you have generated an incorrect color configuration file, you can delete it on the Color Management Options page mentioned above ). If it is a Sony advanced display, as long as the driver system is correctly installed, the corresponding color configuration file will be used, without the need to run the Adobe Gamma program. After my experiments, I think that the better the color configuration file used (or calibrated) by the monitor, the closer the display effect will be to the Adobe RGB (1998) color space.

It is most important to use the correct color configuration file for the monitor. Next, you need to understand two concepts before creating and processing a graphic-color mode and color space. Common color modes include:

• RGB mode: Suitable for most scenarios, such as Web image production and normal print output.
• CMYK Mode: It is recommended to use it only in the case of specific professional printing, and the specific color palette should be selected during graphic processing.

The color mode of the image can be changed. You can change the color mode in the Image menu> mode submenu. In addition, the color space is the meaning of the color range. See the following picture:

In the figure, A represents the color space that the human eye can see, B's black box represents the color space that Photoshop and other software can represent, and C's black box represents the color space that different devices can represent. That is to say, the colors that human eyes can perceive are the most abundant here, and the color ranges that graphic processing software and advanced displays can present are second to that of general displays, digital cameras, scanners, and advanced printers, the worst is the normal printer. Commonly used color spaces in Photoshop include Adobe RGB (1998) color space, sRGB IEC61966-2.1 color space, display color space and printer color space. The following sections further describe them:

• Adobe RGB (1998) Color Space: Corresponding to the black box in B, which is the color range that can be displayed by Photoshop and other software. Although this color range does not have a large scope that the human eye can perceive, it already contains the color range that most computer devices can display. Therefore, Adobe recommends that you use this color space as the color space of the image to be output.
• SRGB IEC61966-2.1 Color Space: The black frame of the digital cameras and scanners corresponding to Figure C has become a standard and is the color space used by most computer peripherals. However, it must be pointed out that it becomes a standard not because it can display a wide range of colors, but because of the different features of various peripherals, only a small color space can be used as a standard to be easily accepted by various peripheral manufacturers. Therefore, Adobe recommends that you use this color space for "prepare to present on multiple devices" graphics (for example, Web image production), but not for professional pre-press graphics, it can be seen that its color range does not even include some range of the advanced printer.
• Display color space: Corresponding to the black box of the monitor in Figure C, the specific color range can be determined by its physical characteristics and the corresponding color configuration file. The color space of high-end and general displays is different. The more upscale the display, the closer the color space is to Adobe RGB (1998), and the worse the display, the closer the color space is to the sRGB IEC61966-2.1. Some software that does not support color space (such as Web browsers, ACDSee 6, and Fireworks) use the display color space to view images.
• Printer Color Space: Corresponding to the black box of the printer in Figure C, the specific color range can be determined by its physical characteristics and the corresponding color configuration file. The figure also shows that the color ranges of normal printers and professional color separation presses are different.

Now, let's get back to the subject. The second step is to specify a color management solution for the image you are processing based on your purpose. The color management solution is a combination of the color pattern and color space mentioned above. In Photoshop, open the color setting option window in the editing menu to set the options. For more information, see Adobe help. The following are my experiences that have been tested repeatedly after reading help. Some of them are different from the suggestions in help, which are for reference only. If you want to use your work for professional printing, you should be a master in this area. This article may not help you much. I have no chance to access professional printers yet, but I think the CMYK color mode should be used and the color configuration file of the printing device should be used as the color configuration file of the graphic.

For general Web graphics production and general print output, Adobe recommends the use of RGB color mode and sRGB IEC61966-2.1 color space as the graphics color configuration file. In most cases, we recommend that you use the Adobe RGB (1998) color space as the color configuration file of the image. Because the current imaging and printing technologies are getting better and better, their color space is far beyond the sRGB standard. You may ask: if I process a graphic when the color space is larger than that of the printer, is it not what I see when I print it out? Indeed. However, the results obtained from my experiments will not be too far apart, and Adobe's graphic processing software also provides the electronic sample function (in the View menu ), you can easily simulate the color space of the printer and the effect of the Color Space of the monitor on the monitor, and process the image in this simulation environment. The premise of correct electronic calibration is that the display is correctly calibrated, so the first step is very important. Note that although Adobe RGB (1998) Color Space facilitates display and printing, it expands the differences between multiple devices (for example, multiple monitors and printers. If you want your work to display almost the same effect on multiple devices (for example, a graph for a Web page), consider using the sRGB color space. I think this is why Adobe recommends sRGB.

Step 3: Save your work. At the beginning, I did not pay attention to it. Not all original graphic formats can save the color configuration file information, and the commonly used PNG file formats of Fireworks won't work. Of course, many formats are supported. You can test them in the "Save as..." command window.

In the end, if you want to print out your shocking work, the post will be full of contents, so there is another key point. In Adobe's help, if your graphics are processed in RGB mode, you only need to install the correct printer driver, you do not need to convert the file from RGB mode to CMYK mode before printing. Because the driver of the printer will automatically call the corresponding color configuration file to process (render) the color in the file and output the same effect as the electronic calibration. If you are processing images in CMYK mode or converting processed images to CMYK mode, you need to disable the color configuration file in the printer driver during printing. In the File menu → print preview pop-up window, the options "Let the printer determine the color" or "Let Photoshop determine the color" are available.

Once again, the above is just my personal experience in certain situations and is for reference only. We recommend that you look at Adobe's authoritative help. However, authority is not truth, and truth is not eternal. What is important is to do more experiments and find the most appropriate color management solution. Wow, there are more and more psoriasis on the street!