Lighting problem

I approximated ribbon by using a lot of polygons, and i used flat shading, i.e I calculate the the normal for every tiny polygons. My problem is one side of the ribbon looks ok, and if i twist the ribbon, i saw the other side, the other side looks too dark, as a matter of fact, I want the other side looks darker, but not too dark, what’s the problem?

Set your ambient light level higher.
For example:

static const GLfloat c3dPropertiesAmbient [] = {0.50, 0.50, 0.50, 1.00};
glLightfv( GL_LIGHT0, GL_AMBIENT, c3dPropertiesAmbient);

[This message has been edited by zoldar256 (edited 08-23-2001).]

are you applying lighting calculations to boths sides of the polygons?