Lecture 11 - Lighting Plans In Practice 1

Question 1

What are technical lighting plans designed for?

Answer 1

To provide a viable plan for the position of all light sources, grip equipment and cabling. Drawn to scale, considers actor and camera movement.
Enable the determination of equipment and power needs - calculations made to determine illumination levels, colour temp, power distribution
Enable crew to set up and rig effectively

Question 2

What needs to be considered in placing units?

Answer 2

Motivation - where is the light coming from?
qualities of light - are shadows hard? Soft?
Colour of the light
Texture - is there any ‘atmosphere’?

Question 3

What is a contrast ratio?

Answer 3

How much light from each source

4:1
key:fill
= four times more illumination from the key than the fill

Question 4

What can we use the inverse square law for?

Answer 4

To determine how much light will reach the subject from a specific luminaire
To determine how far a unit needs to be from the subject to obtain a specific illumination level

fc = cd/ft^2
lux = cd/m^2

Distance = (square root)candle power/illuminance

Question 5

Why is it important to factor in the use of scrims when calculating distance ?

Answer 5

Because scrims and nets reduce overall output in cd

Double scrim = 1 stop less (divide by 2). Single = 1/2 stop (divide by 1.36)

Question 6

How can we use Pythagoras’ theorem to place lighting fixtures?

Answer 6

A high angle beam pointing down to a subject can be considered in terms of the hypotenuse between the floor distance and the height distance of the fixture from the subject.

A^2 + B^2 = C^2

Sin(θ)= opposite/hypotenuse
Height = sin(angle of beam) x illumination distance
Cos(θ)=adjacent/hypotenuse
Floor distance= cos(angle of beam) x illumination distance

Question 7

This lecture looked at a detailed example…

Answer 7

It’s probably worth looking over it again!