Yesterday we looked at practical lights from the point of view of the plein air sketcher.
They also present unique challenges for lighting designers in movies.
In film’s earlier days (above "Mildred Pierce" 1945), film stock wasn’t as sensitive as it is today, so if an actor flipped on an electric light or lit a match, a supplemental light from outside the shot would often have to be switched on at just the right moment to shine on the actor’s face.
In an interior scene where practical lights are visible, the bulbs used (called “practicals”) are generally in the 250 to 500 watt range, and their color is whiter. Normal household bulbs are generally more reddish than other lighting instruments.
Today, more sensitive cameras and digital tools give lighting designers more flexibility. Here’s a screen grab from a film in which Gary Natrass was the Director of Photography. He achieved the natural look in the following way:
“It is lit with just two practical lights: a 100w tungsten bulb in the standard lamp and a 60w tungsten bulb in the table lamp, the fire is real and it was shot on an HPX301 AVCIntra 100 1920x1080i 25np, the camera was set to tungsten balance 3,200k.”
Mildred Pierce set from William Miller Design
Gary Natrass on Film Production Techniques Forum
Practical Lights, Part 1
Film Lighting: Talks with Hollywood's Cinematographers and Gaffers
Set Lighting Technician's Handbook, Fourth Edition: Film Lighting Equipment, Practice, and Electrical Distribution