With Spot Colour Print the specific colours chosen are applied by the press. So if you want to print violet and pink then it is violet and pink ink which is put in the ducts of the press. Full Colour Print can get close to many colours but if your requirement is for an exact match, for instance for a Corporate Letterhead, then Spot Colour is the best solution.

For simple jobs requiring only one or two colours it is often the case that Spot Colour is not only better than Full Colour in terms of colour fidelity but also considerably less expensive.

If you intend to create artwork regularly for spot printing, then it would be essential to purchase a pantone spot colour swatch booklet.

All good graphic design programs such as CorelDraw and Freehand have the ability to enter Pantone reference numbers to provide a representation on screen, but it is not a substitute for using the swatch booklet. 

Whenever artwork is sent to the printing company It is important to make clear on the client copy proof the reference numbers also.