Actually I think The first dial named "shadow" is the darkness of the shadow. If you dont want a light to cast shadows it's best to uncheck in the lights properties. This way it renders faster since it doesn't have to render a shadow map. c1rcle, 3 lights. I think the 2 without shadows are around 70-80%. Just wanted to show how where your lights are at it effects your shadow. Obviously since light causing the strange shadow color is to the right it only hits flat areas of objects. If it had shadows on this wouldn't happen.