First of all, we need to define what a profile actually is.

A profile (sometimes referred to as an ICC Profile) is a file that determines how colours are to be printed for a specific printer and paper. Combined with profile-aware image editing or printing software, it will transform the image from the colour space of the editing software to the colour space for the printer and paper. A colour space is often referred to as the colour gamut, and is basically the range of colours that can be used (this is explained in more detail further on). The result of the transformation means that the colours are changed so that a certain colour in the image will be printed as the same colour on the paper, taking into account various attributes such as the whiteness of the paper (which does have a big impact on the colours that are to be printed).