Charts of Computer Web Color Grays
Variations of gray include achromatic grayscale shades, which lie exactly between white and black, and nearby colors with low colorfulness (chromatic gray). Below is a charts showing the computer web color grays.
► Achromatic Grayscale Shades
An achromatic gray is a gray color in which the red, green, and blue codes are exactly equal. The web colors gray, gainsboro, light gray, dark gray, and dim gray are all achromatic colors.
The colors white and black are not usually thought of as shades of gray, but they can be thought of as shades of achromatic gray, as both contain equal amounts of red, blue and green. White is at the extreme upper end of the achromatic value scale and black is at the extreme lower end of the achromatic value scale, with all the colors normally considered tones of achromatic gray colors in between.
► Chromatic Grayscale Shades
A chromatic gray is a gray color in which the red, green, and blue codes are not exactly equal, but are close to each other, which is what makes it a shade of gray:
Cool grays have noticeably bluish, greenish, or violetish hues:
Warm grays are colors that are noticeably brownish, pinkish grays, or reddish purple grays. The color brown is itself is a dark shade of orange. Brown colors also include dark shades of rose, red, and amber. Pink colors include light tones of rose, red, and orange. These tones of pink become warm grays when they are mixed with gray:
Colors may be specified as an RGB triplet or in hexadecimal format (a hex triplet) or according to their common English names in some cases. A color is specified according to the intensity of its red, green and blue components, each represented by eight bits. Thus, there are 24 bits used to specify a web color within the sRGB gamut, and 16,777,216 colors that may be so specified.
A hex triplet is a six-digit, three-byte hexadecimal number used in HTML, CSS, SVG, and other computing applications to represent colors. The bytes represent the red, green and blue components of the color. One byte represents a number in the range 00 to FF (in hexadecimal notation), or 0 to 255 in decimal notation. This represents the least (0) to the most (255) intensity of each of the color components. Thus web colors specify colors in the True Color (24-bit RGB) color scheme. The hex triplet is formed by concatenating three bytes in hexadecimal notation, in the following order:
● Byte 1: red value (color type red)
● Byte 2: green value (color type green)
● Byte 3: blue value (color type blue)
For example, consider the color where the red/green/blue values are decimal numbers: red=36, green=104, blue=160 (a grayish-blue color). The decimal numbers 36, 104 and 160 are equivalent to the hexadecimal numbers 24, 68 and A0 respectively. The hex triplet is obtained by concatenating the six hexadecimal digits together, 2468A0 in this example.
If any one of the three color values is less than 10 hex (16 decimal), it must be represented with a leading zero so that the triplet always has exactly six digits. For example, the decimal triplet 4, 8, 16 would be represented by the hex digits 04, 08, 10, forming the hex triplet 040810.
The number of colors that can be represented by this system is 166 or 2563 or 224 = 16,777,216.
PS: These texts or information are only quoted for reference. More information you can be found on Wikipedia: Web Colors and Shades of Gray.