Basic Lighting Worktext for Film and Video

Richard Ferncase

• Publisher: Routledge
• Year: 1992
• ISBN:
  9781136044175
• Edition: 1
• Topic: Media & Performing Arts
• Subtopic: Film & Video

Basic Lighting Worktext for Film and Video guides the film and video student through a series of readings, exercises and projects designed to provide the fundamentals of light science. In addition to up-to-date descriptions of equipment and tips on how to use it properly, the book provides numerous set-ups that illustrate the techniques and thoughts behind proper studio and location lighting. From this book, you will learn:
* The fundamentals of light and electricity in film
* The fine distinction of lighting for video versus lighting for film
* How to identify and filter sources such as daylight, tungsten, fluorescent, arc, HNI and industrial discharge lamps
* The use of lensed and open-faced lighting fixtures
* How to modify with barndoors, scrims, snoots, nets, cookies, and other accessories
* Variations on the basic three-point lighting setup
* The duties of each member of a lighting unit
* How to light night exteriors, day interiors, and campfires
* High-key, low-key, and modulated value lighting
* How to scout locations, plan lighting, plots, and pre-rig sets

CHAPTER ONE

The Visible Spectrum

INTRODUCTION

What we know about light goes back long before film and video were invented, and is the result of the findings of several scientists and engineers. Over the course of time, two fundamental, opposing theories of light gradually evolved and competed for dominance in the field of optical science for centuries before they were integrated into one theory by Einstein and others in the twentieth century.

Sir Isaac Newton described light as being composed of tiny particles (or corpuscles) of radiant matter. Newton’s corpuscle theory, however, accepted largely on the basis of his other outstanding achievements in physics and mathematics, could not explain several properties of light, such as diffraction.

By the beginning of the eighteenth century, Newton’s contemporary, Christian Huygens, had popularized the wave theory of light. According to Huygens’ principle, light traveled as vibrational disturbances, similar to sound waves, through the “ether” of space. Huygens’ wave theory gradually took precedence over Newton’s corpuscle theory.

In the late nineteenth century, James Clerk Maxwell enunciated his electromagnetic theory and described light as a vibration of electric and magnetic waves. Maxwell went on to explain that visible light is but a small portion of a wide-ranging spectrum of electric and magnetic waveforms, with frequencies that vary in length.

Maxwell’s theory was proven in 1887 by Heinrich Hertz, who demonstrated the existence of electromagnetic waveforms by transmitting and receiving them in his laboratory. His experiments led to the development of wireless telegraphy, radio, and television.

In 1905, Albert Einstein suggested a return to a modified version of Newton’s theory when he published his concept of photons, or subatomic radiant particles, with the premise that “energy clumps” travel in straight lines, which our eyes perceive as light. Thus, light is now considered a duality that consists of both particles and waves.

THE ELECTROMAGNETIC SPECTRUM

Light travels in straight lines at a constant speed of 186,282 miles per second (mps) and moves in all directions as a transverse wave (see Figure 1.1). Light comprises a very small part of the continuum known as the electromagnetic spectrum, which also includes gamma rays and X rays, radio waves, and alternating electrical current (see Figure 1.2). The radiant energy of the spectrum is classified according to wavelength—the distance between successive waves.

FIGURE 1.1 Light as a transverse wave. Light waves vibrate in all planes perpendicular to the direction of propagation.

FIGURE 1.2 Visible light comprises a very small portion of the radiant energy in the electromagnetic spectrum.

The shortest wavelengths, the cosmic rays, are so small that there are billions of waves to the inch. The longest waves, electrical power waves, measure several miles in length. Physicists use the metric nanometer, or millimicron (one-thousandth of a millimeter), as the measurement of light wavelength. Energies of very long wavelength, such as radio waves, are generally measured by frequency of wave cycles per second, or Hertz. As the speed of electromagnetic energy is constant, frequency is inversely proportional to the wavelength. In other words, the shorter the wavelength, the higher its frequency; the longer the wavelength, the lower its frequency. The wavelength of visible light is discernible to the eye as hue.

WHITE LIGHT

White light, with wavelengths that measure 400–700 nanometers, is actually the sum of hues in the visible spectrum. The hues of the spectrum may be observed in a rainbow or when white light passes through a prism. Newton, who had a predilection for the mystic number seven, identified the spectral primary hues as violet, indigo, blue, green, yellow, orange, and red. The “cool” hues (violet, indigo, blue, and green) have short wavelengths, while the “warm” hues (yellow, orange, and red) have longer wavelengths. Invisible light that has a shorter wavelength than violet is known as ultraviolet; light with wavelengths longer than red, which includes heat, is called infrared. Although the human eye cannot see ultraviolet and infrared radiation, photographic and video media are sensitive to these wavelengths. Film, in particular, is sensitive to heat, which occurs primarily in the infrared band of the spectrum.

The seven colors of the rainbow notwithstanding, for photographic and technical purposes, it is now standard practice to consider white light in terms of its three additive primary colors—red, green, and blue (see Figure 1.3). The secondary or subtractive primary colors are magenta (red and blue), cyan (green and blue), and yellow (green and red).

SPECULAR AND DIFFUSED LIGHT

Light that emanates from a pointlike source and strikes a subject from a single angle or from a few, very similar angles is said to have a specular quality. Specular light is hard, sharp, well-directed, and casts distinct, dense shadows. A prime specular light source is the sun.

When light strikes a subject from a variety of different angles as a result of scattering by an intermediate medium, it is called diffused light. Diffused light tends to be soft, even, and flat; its shadows are less dense and less defined (see Figure 1.4). When clouds cover the sun, the resulting illumination is diffused.

FIGURE 1.3 White light divided into its additive and subtractive primaries—red, green, blue, magenta, cyan, and yellow.

PROPERTIES OF LIGHT

When light strikes the surface of another medium, it may be

reflected—bounced back into the original medium

absorbed—converted by the new medium into another form of energy, such as heat

transmitted and/or refracted—propag...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• CONTENTS
• Preface and Acknowledgments
• CHAPTER ONE THE VISIBLE SPECTRUM
• CHAPTER TWO FILM AND EXPOSURE
• CHAPTER THREE USING ELECTRICITY
• CHAPTER FOUR VIDEO, THE ELECTRONIC MEDIUM
• CHAPTER FIVE CONTROLLING COLOR TEMPERATURE: LIGHT SOURCES AND FILTERS
• CHAPTER SIX CONTROLLING LIGHT QUALITY: LIGHTING EQUIPMENT
• CHAPTER SEVEN MEASURING LIGHT INTENSITY
• CHAPTER EIGHT MANIPULATING LIGHT: DIRECTION AND BALANCE
• CHAPTER NINE LIGHTING CONCEPTS IN PRACTICE
• CHAPTER TEN LIGHTING IN THE STUDIO
• CHAPTER ELEVEN LIGHTING ON LOCATION
• Appendix A: Filters for Light Balancing and Color Compensating
• Appendix B: Some Additional Rosco Filters for Special Applications
• Glossary
• Bibliography