The accurate reproduction of color has always been a headache. The use of terminal devices for various color images is extremely heavy. For example, monitors, digital cameras, scanners, printers, etc., how to make the colors consistent between devices It has increasingly become a research hotspot. sRGB is a color space definition that provides a standard way of defining colors so that external devices and software applications can use the same color description. With the wide application of sRGB in various color fields, it quickly became an international standard. This article intends to explore four aspects of its origin, color implementation methods, inadequacies, and future development prospects.
First, the origin of sRGB
For advanced printing and graphic design professionals, image display devices with relatively good color processing capabilities should belong to Apple’s equipment, as opposed to the company’s
ColorSync system, which is an operating system-level CMS (Color Management System). Apple's products are very good in terms of performance, but they cannot be widely used on PCs. Microsoft took notice of this. In 1997, the company and Hewlett-Packard Co. created the sRGB color space.
That is "Standard Red Green Blne" or standard RGB, which is based on
PC's 32-bit color space.
When sRGB is used by digital image display devices such as monitors, scanners, printers, and video cameras, it can improve color matching capabilities between digital devices and printouts, ensuring consistent color.
Before the sRGB technology was implemented in the PC, the effect of the color processing function of Microsoft's Windows operating system was not significant, but then Windows 2000 provided the sRGB integration of the entire ICM2.0, making the sRGB color space rapidly popularized in color display terminals. .
Second, sRGB color implementation method
We know that different devices use different mechanical devices to produce colors: the general printer is based on subtractive color systems, usually using cyan, magenta, yellow, and black, ie CMYK, starting with white and subtracting red, green, and blue Colors to get color and black; display color display is based on additive color theory, starting with black, starting to increase red, green and blue to get a variety of colors; sRGB color space is to use many values ​​to accurately outline the color The red, green, and blue elements compose the pixels in the digital image and the color areas such as images, charts, and texts by these elements, so as to make up for the difference in the effect of color expression due to mechanical differences. The sRGB standard color space definition can meet the need to improve the exact color matching between software applications and hardware devices.
Third, the deficiencies of sRGB
Since the gamma level affects the accurate reproduction of the midtones of the image, it is important to set a consistent gamma level between all devices. This is an absolutely necessary and important thing in properly managing the color flow. . If the gamma level between devices is inconsistent, it is impossible to correctly implement color reproduction between these devices. The de facto standard used by many image editing programs and display calibration systems when opening an image is: A size assumed by Mao OS is
1.8 gamma. But sRGB on the PC uses a gamma of 2.2. Therefore, the matching of colors in a mixed environment of Macs and PCs and mixed software packages is not an easy task. This is one of the significant inconveniences that sRGB brings to the operators, which we attribute here to the insufficiency of sRGB.
In addition, although sRGB is a big improvement for PC users, most color experts still believe that sRGB has a fatal weakness: Compared with print media, the color range of displays is affected by color and hue. With severe limitations, the sRGB color workflow is generally not optimally reproduced. This is why the number of brands that currently implement sRGB in the display area is very small.
But in scanners and printers, after HP, almost all vendors have achieved
sRGB requirements. The current solution to this more deadly problem also requires the technical efforts of numerous display manufacturers.
Fourth, the future development of sRGB
Now, the alliance formed by Microsoft and Hewlett-Packard has released sRGB64. This standard adopts 64.
Bit to reproduce color, but not 32-bit. sRGB64 essentially doubles the accuracy of the color, with red, green, and blue values ​​below zero (no color) and above 1.0 (the largest possible color). This extra space allows for more precise operation of colors, in addition, using this method, the operator never loses information. For example, if you compress the blue range in a 32-bit color image to zero, the blue tone range will become zero; if you need to restore blue, all the original tone expansion will be Disappears, and the resulting image will get a bluish projection. But in the case of 64-bit pictures, all the blue tones still exist. That is, values ​​outside of the color range are not clipped, but are saved for future viewing and use, as well as other operations, without affecting the original image.
The current situation is: Although there are still some deficiencies in the sRGB color space, it also has its own many advantages. In fact, sRGB's 2.2 gamma value has excellent perceptual coding ability, can almost match the physical properties of computer and video display, and is the assumed gamma point of various Windows versions, which makes sRGB become a management A good application for color graphics applications and print colors.
First, the origin of sRGB
For advanced printing and graphic design professionals, image display devices with relatively good color processing capabilities should belong to Apple’s equipment, as opposed to the company’s
ColorSync system, which is an operating system-level CMS (Color Management System). Apple's products are very good in terms of performance, but they cannot be widely used on PCs. Microsoft took notice of this. In 1997, the company and Hewlett-Packard Co. created the sRGB color space.
That is "Standard Red Green Blne" or standard RGB, which is based on
PC's 32-bit color space.
When sRGB is used by digital image display devices such as monitors, scanners, printers, and video cameras, it can improve color matching capabilities between digital devices and printouts, ensuring consistent color.
Before the sRGB technology was implemented in the PC, the effect of the color processing function of Microsoft's Windows operating system was not significant, but then Windows 2000 provided the sRGB integration of the entire ICM2.0, making the sRGB color space rapidly popularized in color display terminals. .
Second, sRGB color implementation method
We know that different devices use different mechanical devices to produce colors: the general printer is based on subtractive color systems, usually using cyan, magenta, yellow, and black, ie CMYK, starting with white and subtracting red, green, and blue Colors to get color and black; display color display is based on additive color theory, starting with black, starting to increase red, green and blue to get a variety of colors; sRGB color space is to use many values ​​to accurately outline the color The red, green, and blue elements compose the pixels in the digital image and the color areas such as images, charts, and texts by these elements, so as to make up for the difference in the effect of color expression due to mechanical differences. The sRGB standard color space definition can meet the need to improve the exact color matching between software applications and hardware devices.
Third, the deficiencies of sRGB
Since the gamma level affects the accurate reproduction of the midtones of the image, it is important to set a consistent gamma level between all devices. This is an absolutely necessary and important thing in properly managing the color flow. . If the gamma level between devices is inconsistent, it is impossible to correctly implement color reproduction between these devices. The de facto standard used by many image editing programs and display calibration systems when opening an image is: A size assumed by Mao OS is
1.8 gamma. But sRGB on the PC uses a gamma of 2.2. Therefore, the matching of colors in a mixed environment of Macs and PCs and mixed software packages is not an easy task. This is one of the significant inconveniences that sRGB brings to the operators, which we attribute here to the insufficiency of sRGB.
In addition, although sRGB is a big improvement for PC users, most color experts still believe that sRGB has a fatal weakness: Compared with print media, the color range of displays is affected by color and hue. With severe limitations, the sRGB color workflow is generally not optimally reproduced. This is why the number of brands that currently implement sRGB in the display area is very small.
But in scanners and printers, after HP, almost all vendors have achieved
sRGB requirements. The current solution to this more deadly problem also requires the technical efforts of numerous display manufacturers.
Fourth, the future development of sRGB
Now, the alliance formed by Microsoft and Hewlett-Packard has released sRGB64. This standard adopts 64.
Bit to reproduce color, but not 32-bit. sRGB64 essentially doubles the accuracy of the color, with red, green, and blue values ​​below zero (no color) and above 1.0 (the largest possible color). This extra space allows for more precise operation of colors, in addition, using this method, the operator never loses information. For example, if you compress the blue range in a 32-bit color image to zero, the blue tone range will become zero; if you need to restore blue, all the original tone expansion will be Disappears, and the resulting image will get a bluish projection. But in the case of 64-bit pictures, all the blue tones still exist. That is, values ​​outside of the color range are not clipped, but are saved for future viewing and use, as well as other operations, without affecting the original image.
The current situation is: Although there are still some deficiencies in the sRGB color space, it also has its own many advantages. In fact, sRGB's 2.2 gamma value has excellent perceptual coding ability, can almost match the physical properties of computer and video display, and is the assumed gamma point of various Windows versions, which makes sRGB become a management A good application for color graphics applications and print colors.
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