A Sense of Depth

I've just finished reading Lighting for Digital Video and Television by John Jackman and It has given me a load of pointers on the cinematography front.

Here's what the book had to say on basic lighting principles.

A lot of good lighting is about creating a sense of 3D depth on a 2D plane. If a scene is lit uniformally with equal levels of light intensity coming from all sides then the image will look flat. Of course when there are different levels of light coming from different angles or mabye just one light sourse at an angle then as one might expect objects will be more defined.

Like so... (I got this image from google, I'm not this provicent with 3D modeling sadly)

A common tool is to diffuse the light to make it softer. This has the effect of the light seeming to "wrap around" an object as well as the surface progressing from light to dark more gradually. The transfer region is the area of trasition from light to dark and the softer the light the larger the transfer region. When light is this soft the hilight isn't just pure white, it picks up some of the surrounding colour.

If we want to add more definition (and in scenarios that are more than just eggs and balls we frequently do) then a second light known as a fill light is added in a similar position but on the other side of the camera to the first light - known as the key. This new light should be less intense that the key light otherwise we will have a flat image. A lot of the feel of a scene is the relationship between the key and the fill. Finally to add more definition a backlight is often added shining on the obeject from behind, not the backgroud which is lit seperately. There are a handful of varities of backlight depending on its exact placement behind the subject. Finally it is important to remember that a backlight pointing towards a camara is going to be stronger than a light pointing away from the camera as light "skips" off the object.