subtractive lighting ?

A chap on ephotozine suggested i should use subtractive lighting for this shot,

http://www.ephotozine.com/gallery/showlargepic.cfm?photoid=112355&start=32

I'm guessing it might be something like fill in flash? Can anyone explain subtractive lighting (in simple terms) please?
john

It just means blocking the source of unwanted light, usually harsh midday light.

You might of course wish to provide an alternative light source, such as fill flash or a reflector to add a bit of contrast.

Thanks George, I think the guy was trying to blind me with his skills and knowledge! I looked it up the other day and found out what it was. I'm going for the reflector option, and I think I'll try to build a screen, using a collapsible tent pole. Do you think that might work?
john

A screen and a reflector are the obvious way to go. You could also try filtering the light through something like the material on a softbox, or the diffusing panels used over fluorescent lighting. Some of them have a "warming" effect which might be useful. Experiment beforehand.

The only trouble with using screens and reflectors outdoors is wind. However, if you are photographing pretty girls it shouldn't be too difficult to find volunteers to assist you!