Lighting Ratios

[GDMaclarn]

Greetings all. My employer has had me going in eastern europe so little chance to participate.
Can anyone give me a good understandable explanation of lighting ratios using flash heads or constant light sources?
With thanks

Graeme

[Darey]

Graeme,
Have a look at the following link, it will give you all you need.

http://www.youtube.com/watch?v=zQBa2y9NYIE

Happy shooting.