Intensity and Shadow

Intensity refers to the relative brightness of a light. I like the term “intensity” over “brightness” because of the subjective nature of light. A dim light in a dark room can feel very intense. A very bright light can be underwhelming when in competition with the sun.

Shadow is the absence of light and can only exist in light’s presence. They are the Yin and Yang, the positive and negative, the hot and the cold that create balance.

We could have a conversation about the physics of light, which would be fun, but I think that’s best done when you have a handle on the craft. So to put simply, if you want to control the intensity of the light you can change the power, proximity, or quantity.

In your kitchen, when you flip a light switch, the lights go on at full power – giving off as much illumination as they can. Full speed ahead! You could replace those lights with brighter or dimmer lights who then use less electricity. In your living room, you might have a dial that dims your lights – brighter, dimmer, half way in between. That dial is simply changing how much electricity flows through the lights. They have a minimum (off) and a maximum (bright) amount of light they can give off.

On the stage we control our lights using a light board and tell them to “turn off!”, “be as bright as you can”, “give me 45% of what you can do”.

All this is about changing the amount of power being given to the fixture.

We can also change how bright a light is perceived by changing how close it is to an actor. In a dark theatre, sitting in the audience, you could try to illuminate the actors with your phones flashlight. That’s a bright idea, but it probably won’t work, you’re too far away; however, if the actor were to hold a phone under their face with the flashlight on you would have a very

Let’s go back to our example of sitting in a dark theatre, sitting in the audience, holding a phone. Your phone, by itself, will do very little; but the whole audience and their multitude of flashlights will fill the entire auditorium. This is one of the reasons why when you look up in a theatre, the space is filled with lights – the combined work of the lights fill the stage – together they do more than any single light could.

Visibility – This might be quite obvious, but intensity is the primary element to achieve visibility. The light needs to be on to see the actors. Less obvious is that there is a necessary balance in which the eye is comfortable watching the stage. Too dim and we strain our eyes to see. Too bright and our eyes are overwhelmed.

Composition – The presence and absence of light can help craft the define the composition of the stage. Lighting the entire space becomes visually exhausting. Lighting only a small portion and leaving everything else in blackness makes the audience long to know what’s happening in the dark. A balanced illumination can help drive the eye – bright where you want us to look and dim where there’s no action is often the best choice.

Form – When there are lights come from various directions, contrast in illumination can create contrast in form. Brighter from one side and dimmer from the other creates shadow and then lights it up slightly so we can fully see an actor. We’ll talk more about that in the next lesson.

Mood – This is a dangerous one because often times a designer will be tempted to create mood with dim light, but a dim stage isn’t sustainable look, we can’t watch it very long before we get tired. If you want to create a moody look with intensity, the secret is shadow – the absence of light created by the presence of light.

Style – The amount of shadow created by illumination can help support the performance’s style. For example, a “well lit” stage, meaning there aren’t a lot of heavy shadows, would support the style of realism. For example, the presence of a bright follow spot, highlighting and actor, would support the style of musical theatre.