Don't just work against the light. Work with it, too.

A preamble: If you haven’t read my previous blog--the one about working against the light--read that before you read this one. That one is about a fundamental rule. This one is about how to apply it.

Okay. The blog itself: Let’s start with something I said to do in the previous blog. I mentioned that the light comes from behind your subject. And I said that one implied light source makes for both prettier film and easier filming.

A few of my more astute readers raised an important question: “What do you do when you’re shooting two people having a conversation?”

Good question. Most people talk while facing each other, and most filming is done to show people’s faces. So in a scene involving a normal conversation, if somebody is backlit, the other somebody is going to be front lit.

Unless you move the light source, which you don’t. Any kind of movement--and I’m talking about props, actors, and cameras as well as light sources--needs to be motivated. There needs to be a reason. I’ll dwell on that in a future blog, but for now, let’s just call it a law with regard to a light source. The sun doesn’t change position in the sky in the middle of a conversation just so that the person talking looks better. Wherever the sun is, the sun stays. Same for lamps, candles, the moon, and reflections off the water.

So what do you do?

The simple answer is an old Hollywood rule: Put the woman in the more flattering light. Backlight is generally more flattering than front or side light, so that’s where she goes.

The not-quite-as-simple answer has two parts. The first is to light for the wide. The second is to place your actors so that if meaning can be inferred from lighting, the correct lighting falls on the appropriate actor.

Lighting for the wide is something you do anyway. The wide is often called the establishing shot because it establishes where you are, what time of day it is, and what conditions you’re operating under. In a park, late afternoon, winter. Under a bridge, night, raining. That sort of thing.

Once you’ve established your wide, place your actors. But don’t shoot anything until you’ve considered the other shots you’re going to get of them. You’ll probably do a close up on each of their faces, so think about how the light will fall on them when you get there.

You might find that one of them wants to be in shadow because it adds a nice menacing touch to the scene. Or maybe your beautiful actress has just betrayed your actor. She could have side lighting to emphasize what few flaws her porcelain skin has.

No matter what you decide, remember what I said about ambience. Ambience fills shadows. And in a close up, you have permission to fill them a bit. Our eyes see into shadows when we’re close enough to them, so unless you have a good reason for putting big pools of black on screen, brighten them up at least enough to show some detail.

It’s the details that make a difference. And I’m not just talking cinematography, either.