RGB color mode is an industrial color standard that produces various colors by varying and combining the red (R), green (G), and blue (B) color channels. RGB represents these three channels, and this standard encompasses nearly all the colors perceptible to the human eye, making it one of the most widely used color systems.

HSL (Hue, Saturation, Lightness) is a representation of the RGB color model in a cylindrical coordinate system.

• Hue (H) is the basic attribute of color, commonly referred to as the color name, such as red, yellow, etc.
• Saturation (S) indicates the purity of the color; higher saturation means purer color, while lower saturation results in a grayish tone, ranging from 0-100%.
• Lightness (L) ranges from 0% (darkest) to 50% (midpoint) to 100% (brightest).

HSV (Hue, Saturation, Value) is a color space created by A. R. Smith in 1978, also known as the Hexcone Model.

CMYK is a color mode used for printed materials that relies on reflected light. When reading the content of a newspaper, it is the light from the sun or a lamp that reflects off the newspaper and into our eyes, allowing us to see the content. It requires an external light source; you cannot read a newspaper in a dark room.

Converting RGBA colors to hexadecimal color codes involves transforming R, G, and B values, which are between 0 and 255, directly from decimal to hexadecimal. The alpha value (A) is between 0% and 100%, converted to a corresponding number between 0 and 255 (A*255), and then converted to hexadecimal. For example: RGB 46,139,87 converts to hexadecimal color code #2e8b57, RGBA 46,139,87,0.6 converts to hexadecimal color code #2e8b5799.