Overview of Inverse Square Law of Lighting

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Transcript of Overview of Inverse Square Law of Lighting Video

NARRATOR 1: A man standing near a variety of lamps.

NARRATOR 2: Learning to position lighting correctly is crucial to get the most out of the lighting you are using. Listen to this overview to learn more.

BRYAN: People often ask, so what's the right wattage, or type of light for me? And I often tell them, even more important than the wattage, or the type of light, is the position of the light. Partly, that's because light uses what's called "the inverse square law," which means that as a light gets closer, we square the amount of light delivered.

NARRATOR 1: A white gooseneck desk lamp is shown.

BRYAN: For instance, if a light is two feet away from an object...

NARRATOR 1: The man moves the lamp closer to a notebook on a table.

BRYAN: ...and we move it so that it's one foot away...you'd think that it's twice as bright. It used to be two feet, now it's one foot. But instead, it's four times as bright, because we squared the amount of light. That's a powerful principle. If it was one foot away, and we move it so it's six inches away, it's another four times as bright. So we squared the amount of light delivered again. That can be done with a gooseneck desk lamp, with a gooseneck floor lamp to bring the light right where it's needed. Whatever we're doing, like reading, or writing, or sewing, with a clamp-on light, with a swing arm lamp, and with a light with a very long, adjustable gooseneck, or swing arm.

NARRATOR 1: An example of each of the lamps is shown.

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