Web Colour Charts and the Colour Wheel

Colours on web pages are specified using the RGB model, in which every colour is built from a mixture of red, green and blue light. Because screens emit light, combining these three primaries at full strength produces white, while their absence produces black, and varying the proportions yields the full range of displayed colours. In HTML and CSS, each of the three components is given a value, commonly written as a six-digit hexadecimal code such as the form beginning with a hash sign, where pairs of digits set the amount of red, green and blue.

A web colour chart is a reference table that pairs colour swatches with their codes, so a designer can pick a colour and copy the exact value needed to reproduce it. Charts often include named colours that browsers recognise, along with their equivalent hexadecimal codes. Having these values to hand makes it straightforward to set the colours of text, backgrounds and borders consistently across a site, since the same code always produces the same colour.

A colour wheel arranges hues in a circle to show how they relate to one another. Colours opposite each other on the wheel are complementary and contrast strongly, while colours near each other are analogous and blend smoothly. Designers use the wheel to choose combinations that work well together, then translate the chosen hues into RGB codes for use in the page. Together, a colour chart and a colour wheel link the visual choice of colours to the precise codes a web page requires.

Frequently asked questions

What does an RGB colour code represent?

It specifies how much red, green and blue light to mix, usually as a six-digit hexadecimal value, to produce a particular colour on screen.

What is a web colour chart for?

It is a reference that pairs colour swatches with their codes so designers can choose a colour and copy its exact value for use in HTML or CSS.

What does a colour wheel show?

It arranges hues in a circle to reveal their relationships, such as which colours contrast as complementaries and which blend as analogous neighbours.