The use of web colors is of course a basic tool in web design and is actually not as complicated as it may seem at first glance. A brief introduction: there are two basic color systems: Additive color mixing and subtractive color mixing. Light colors that are displayed either with spotlights or on screens are additive color mixing. Roughly speaking, this means “red + green + blue = white”.

All ‘physical’ colors that are applied to a surface, for example, are referred to as subtractive color mixing.

The color space of subtractive colors behaves differently than that of additive colors. Instead of red, green and blue (RGB), we are dealing with the primary colors cyan, magenta and yellow: CMYK. The “K” stands for “key”, the color depth – i.e. the black component. Roughly speaking, this means: “Cyan + Magenta + Yellow = Black”.

Web colors in HTML and CSS – RGB vs. HEX

CSS can also be used to define colors on the web – however, this works very differently for web colors than for print colors. A good example of the difference is the color cyan. There is actually no “light color” that corresponds to the print color cyan. Nevertheless, there is a web color “cyan” with the HEX code #00FFFF and the RGB values 0, 255, 255. On the screen, this HTML cyan actually resembles the printed color cyan – but the two colors have nothing to do with each other from a purely technical point of view.

In HTML code or CSS code, colors can therefore be specified as RGB values or as so-called HEX values (HEX Color Code). Sometimes the colors used in web design are also called HTML colors or CSS colors – the more general term web colors would be more appropriate. Both systems have one thing in common: the color is formed from a combination of red, green and blue – hence the abbreviation RGB. The red, green and blue components of the desired color are each specified via a value – together they then result in the desired hue.

The composition of such RGB codes (“RGB colors”) is relatively easy to explain. The first three numbers stand for the red, green and blue components. For the color intensity, 8 bits or 256 levels are available for each hue. The value is specified as a decimal number – zero “0” is the lowest value and “255” the highest. With an RGBa color space, the alpha channel is also available to determine the transparency of a hue or color area. The zero “0” stands for complete transparency and “255” for full opacity.

The HEX Color Code (“HEX colors”) is a little different. Here, too, you basically have 8 bits or 255 levels per color tone to choose from – i.e. 255 color tones per basic color red, green and blue. The number “00” has the lowest value, the letter “FF” the highest value. The desired hue is then not specified as a decimal number, but as a hexadecimal number. The three values are then combined to form a six-digit combination of numbers and letters – the HEX Color Code.

Here are a few tables with the respective HEX values and a color field that represents the respective hue: