Colours can be defined in many different contexts in HTML, for example:
- File wide background colours
- Font colours for blocks of text
- Background colours in tables
Although all these designations have since been characterised as deprecated by the W3 consortium, which means they should no longer belong to the language standard in the future. The reason is that all of these colours can be defined with the help of style sheets. CSS, not HTML, is now the language for graphics. Nevertheless, it is worth learning how to define these colours in HTML, because although the same functions exist in CSS, the language also has many more possibilities. We will discuss the subject from a CSS viewpoint in a later section.
There are fundamentally two possibilities for defining colour in HTML:
- Choose the desired colour in hexadecimal form through designations of RGB values (RGB= red/green/blue)
- Through the designation of a colour name
If you enter hexadecimal inputs, then you work independently of the browser, and you have the total freedom of choosing from 16.7 million colours.
If you choose to simply the enter the colour name, then you bypass the somewhat complicated method of defining a colour in the hexadecimal mode. However, there are currently only 16 standardised colours. Additional colour names exist, but they are browser dependent.
The hexadecimal entry of colours
If you wish to define colours directly in the hexadecimal mode, then you must select the desired colour from designations for the three base colours, red, green and blue.
An Example:
<body bgcolor= “#808080”> <!– dark grey file background –>
<table bgcolor= “#00C0C0”> <!– blue green table background –>
<hr color= “#CC00CC”> <!– violet divider –>
Explanation:
Every hexadecimal colour definition has six digits and follows the formula: #RRGGBB
First notate a “#”. Six characters then follow and define the colour. The first two define the red value of the colour, the second two define the colour’s green value, and the final two define the colour’s blue value.
Hexadecimal Digits:
0 (corresponds to the decimal 0)
1 (corresponds to the decimal 1)
2 (corresponds to the decimal 2)
3 (corresponds to the decimal 3)
4 (corresponds to the decimal 4)
5 (corresponds to the decimal 5)
6 (corresponds to the decimal 6)
7 (corresponds to the decimal 7)
8 (corresponds to the decimal 8 )
9 (corresponds to the decimal 9)
A (corresponds to the decimal 10)
B (corresponds to the decimal 11)
C (corresponds to the decimal 12)
D (corresponds to the decimal 13)
E (corresponds to the decimal 14)
F (corresponds to the decimal 15)
Therefore, a hexadecimal digit can have 16 different conditions.
Take Note:
There are 16 base colours that can be displayed by every VGA compatible screen
There are also 216 colours, which have developed into the internet’s standard colour palette. We will discuss these colour palettes in greater detail in a separate section.
In order to make defining colours easier, colour selectors also exist.
Names for the basic 16 colours
An Example:
<body bgcolor= “black”> <!– black file background –>
<table bgcolor= “aqua”> <!–light blue table background –>
<hr color= “red”> <!– red divider –>
Enter the desired colour names in the place where colour designations are allowed.
In order to get an overview of the available colours, you can enter the example above. The hexadecimal values, that correspond to colour names, will then be shown.