each pixel can have colour and transparency associated with it the range of colours available depends on the display system being used for examplemono chrome displays only allow black and whitewhere as grey scale display only allows various shades of grey to be displayed on modern systems it is usually possible to represent wide range of colours using the tradition rgb colour codes (where represents redg represents green and represents bluein this encoding solid red is represented by code such as [ where as solid green is represented by [ and solid blue by [ based on this idea various shades can be represented by combination of these codes such as orange which might be represented by [ this is illustrated below for set of rgb colours using different redgreen and blue valuesin addition it is possible to apply transparency to pixel this is used to indicate how solid the fill colour should be the above grid illustrates the effect of applying % and transparency to colours displayed using the python wxpython gui library in this library the transparency is referred to as the alpha opaque value it can have values in the range - where is completely transparent and is completely solid