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Grayscale forms the basis for creating a graphic or when calibrating a monitor so that images appear true to color. On the screen, not only the maximum and minimum luminance that create brightness and darkness are important. Color nuances and shades of gray should also be displayed perfectly. This can be achieved through transmission of the RGB colors and through other settings.
A color palette with 256 colors is available for the color display, in which the red, green and blue components have the same color value. This leads to a gradation of different tones. They are identified and coded by a number. Pure black is defined with a value of 0, while pure white has a value of 255. Intermediate values enable the gray coloring with gradations of brightness. They include a total of 256 shades of gray.
All hues are grouped together in the RGB palette and are labeled with a specific value. This makes it possible to create digital images with a very specific coloring or to preserve colors on a screen.
RGB describes the color space that is created with the tones red, green and blue and is important for technical devices such as televisions, smartphones and PC monitors. These three colors are called light colors and cannot be reproduced in their pure form. Rather, they are used for pure additive color mixing and are composed and coded in 256 levels.
A shade of gray is always defined as an intermediate value of 192, from which 256 possible gradations of brightness arise. All color tones, which are correspondingly stored between 0 and 255, result in the various shades of grey.
In photography, gray images can be created by reducing color tones, for example when depicting landscapes, portraits, fabrics and products. The effect is clearly visible using the example of black-and-white photography. It not only shows white and black areas, but rather consists of many shades of gray. Such a photograph is possible because the coloring has been reduced while the full color depth is retained. This creates a clearly differentiated formation of levels.
The settings can be made directly on the camera or later during image processing. Special shades of gray can be activated on the monitor using a filter. Grayscale also plays a role in the evaluation of basic geodata by WebAtlasDE and cartography.
Grayscale images can be created using special techniques related to the values of the RGB palette. In general, the human eye perceives the color difference, perceives the red color as lighter than the blue and the green as lighter than the red. In order to produce gray, a threshold is determined. If this is below the gray values, darker levels arise up to the black color. If it is above the value, the gray values become lighter to white.
Depending on the video signal, the transmission of the RGB component causes the perception of more brightness on the monitor. Accordingly, settings can be made that intensify or reduce the color tones. An LCD screen typically offers a resolution of 256 levels for the primary colors. With the same control, there are gray tones between black and white. Mixed colors are created with different controls.
