Using Diffuse Reflection and Shadow to Reveal Texture
In any discussion of surface definition, we must talk about texture. This is why we promised at the beginning of this chapter that all examples would be nearly two dimensional. We will first look at a photograph that fails to reveal the texture of the subject. This will help us analyze the problem and come up with a better solution. 4.12 The solution to the impossible lighting requires placing the lights for even illumination and using polarizers to prevent glare. The axis of the light...
Capitalizing On Diffuse Reflection
Photographers are sometimes asked to photograph paintings, illustrations, or antique photographs. Such copy work is one simple example of a circumstance in which we usually want only diffuse, and not direct, reflection. Because this is the first concrete demonstration of lighting technique in this book, we will discuss it in great detail. The example shows how an experienced photographer thinks through any lighting arrangement. Beginners will be surprised at the amount of thinking involved in...
The Angle of Light
What sort of lighting might accomplish this To answer that question, let us begin by looking at a standard copy setup and at the family of angles that produces direct reflection. Figure 4.1 shows a standard copy camera arrangement. The camera is on a stand and is aimed at the original art on a copy board beneath it. Assume that the height of the camera is set so that the image of the original art exactly fills the image area. We have drawn the family of angles from which a light, or lights, can...
Absorption
Light that is absorbed by the subject is never again seen as visible light. The absorbed energy still exists, but it is emitted by the subject in an invisible form, usually heat Figure 2.14 . Like transmission, simple absorption cannot be photographed. It is visible only when we compare it to other light in the scene that is not absorbed. This is why highly light-absorbing subjects, such as black velvet or black fur, are among the most difficult things to photograph. Most subjects absorb part,...
What Kind Of Camera Do I Need
Asking What kind of camera do I need may seem silly to experienced photographers. But we have taught this material, we know how many perfectly intelligent students ask it, and we have to answer it. There are two good answers, and they contradict each other slightly. The weight we place on each answer matters more than the answers themselves. Successful photographs depend on the photographer more than the equipment. Inexperienced photographers work best with the camera with which they are...
Contrast
The third important characteristic of a photographic light is its contrast. A light source has high contrast if its rays all strike the subject from nearly the same angle. Light rays from a low-contrast source strike the subject from many different angles. Sunlight on a clear day is a common example of a high-contrast light source. Notice that the rays of sunlight in Figure 2.4 are parallel to one another. They all strike the subject at the same angle. The easiest way to recognize a...
What Is Light
A complete definition of the nature of light is complex. In fact, several Nobel Prizes have been awarded for various contributions to the working definition we use today. We will simplify our discussion by using a definition adequate for applied photography. If you are still curious after reading this, see any basic physics text. Light is a type of energy called electromagnetic radiation. Electromagnetic radiation travels through space in tiny bundles called photons. A photon is pure energy and...
The Principles
The appearance of glass is determined by many of the same principles we discussed in the preceding chapter on metal. Like metal, almost all reflection produced by glass is direct reflection. Unlike metal, however, this direct reflection is often polarized. We might expect the techniques used for lighting glass to be similar to those used for metal. We might find a polarizing filter useful more often, but otherwise apply the same methods. However, this is not so. When we light metal, we are...
Complex Surfaces
In this book we will use the term complex surface to mean a single surface that requires both diffuse and direct reflection to define it properly. Glossy wood is a good example. Only direct 4.25 The result of the technique illustrated in Figure 4.24 detail in the blacks, plus legible type on the label. 4.25 The result of the technique illustrated in Figure 4.24 detail in the blacks, plus legible type on the label. reflection can tell the viewer that the wood is glossy, but diffuse reflection is...
The Size Of The Light
Selecting the size of the light is one of the most important steps in studio lighting. Time of day and weather determine the size of the light outdoors. The previous chapter discussed how adjusting the size of the light makes the edges of the shadows harder or softer. If two shadows record as the same gray, a hard shadow will be more visible than a soft one. For this reason, a hard shadow often increases the illusion of depth more than a soft one. When we understand this we have another way to...
Diffuse Reflection
Diffuse reflections are the same brightness regardless of the angle from which we view them. This is because the light from the sources is reflected equally in all directions by the surface it strikes. Figure 3.1 shows a diffuse reflection. In it we see light falling on a small white card. Three people are pointing their cameras at it. If each of these individuals were to photograph the white card, each of their pictures would record the subject as the same brightness. On film, the image of the...
Breaking the Inverse Square Law
Did it alarm you to read that the camera that sees the direct reflection will record an image as bright as the light source How do we know how bright the direct reflection will be if we do not even know how far away the light source is We do not need to know how far away the source is. The brightness of the image of a direct reflection is the same regardless of the distance from the source. This principle seems to stand in flagrant defiance of the inverse square law, but an easy experiment will...
Dedications
I can't pay back the small handful of people who taught me most, but I can follow their example and teach others as well as I can. This book is my effort to do just that. These are those people Ruth Reavis, who expected me to work harder Geneva Highfill and Wanda Walton, who taught the language Betty Welch, who taught the mathematics and Ross Scroggs, Sr., who taught me about photography and about the difference between humans and apes. Since then, I've tried my best to become a human. Whatever...
The Family Of Angles
Our previous diagrams have been concerned with only a single point on a reflective surface. In reality, however, each surface is 3.5 Two clues tell us this picture was made with a small light source hard shadows and the size of the reflection in the mirror. 3.5 Two clues tell us this picture was made with a small light source hard shadows and the size of the reflection in the mirror. 3.6 A larger light softens the shadow. More important, the reflection of the light now completely fills the...
Photographing Cylinders Increasing Tonal Variation
Now we are going to look at a cylinder and the special problems that it presents. Figure 5.18 is a cylindrical object, but the tonal variation does not reveal the shape very well. Because the lighting is so even across the entire surface of the wooden bowling pin, it is difficult to tell whether the object is three dimensional. The photograph does not contain enough visual clues for our brains to make an informed decision. The problem is caused by the fact that the sides of the cylinder are not...
Perspective Distortion
Subjects appear smaller when they are farther away. Furthermore, if the subject is three dimensional, the part of the subject that is farther away appears to be smaller than the closer part of the same subject. Similarly, the closer part of the same subject appears to be larger. We call this effect perspective distortion. Some psychologists believe that infants perceive more distant subjects to be actually smaller. No one is sure about this because by the time we are old enough to talk about...
Polarized Direct Reflection
A polarized direct reflection is so similar to an ordinary direct reflection that photographers often treat them as the same. However, these reflections offer photographers several specialized techniques and tools for dealing with them. Like the direct reflection, only one viewer in Figure 3.8 will see the reflection. Unlike the direct reflection, an image of the polarized reflection is always substantially dimmer than a photograph of the light source itself. A perfectly polarized direct...
The Inverse Square Law
A diffuse reflection gets brighter if we move the light source closer to the subject. If we needed, we could calculate this change in brightness with the inverse square law. The inverse square law says that intensity is inversely proportional to the square of the distance. Thus, a light at any particular distance from the subject will light the subject with an intensity four times as bright as the same light twice as far away. Similarly, a light will have nine times the intensity of the same...
The Case of the Disappearing Glass
The Principles The Problems The Solutions Two Attractive Opposites Bright-Field Lighting Dark-Field Lighting The Best of Both Worlds Some Finishing Touches Defining the Surface of Glassware Illuminating the Background Minimizing the Horizon Stopping Flare Eliminating Extraneous Reflections Complications from Nonglass Subjects Liquids in Glass 112 113 113 116 117 120 120 124 126 130 132 150 150 152 152 156 160 162 162 166 166 168
Direct and Diffuse Transmission
So far we have talked about direct transmission, in which light passes through a material in a predictable path. Materials such as white glass and thin paper scatter the light rays in many random, unpredictable directions as they pass through. This is called diffuse transmission Figure 2.13 . Materials that produce diffuse transmission are called translucent to distinguish them from transparent materials, such as clear glass, which do not significantly diffuse the light. Diffuse transmission is...
What Are The Principles
To photographers, the important principles of light are those that predict how it will behave. Some of these principles are especially powerful. You will probably be surprised to find how few they are, how simple they are to learn, and how much they explain. We discuss these key principles in detail in Chapters 2 and 3. They are the tools we use for everything else. In later chapters we put them to work to light a wide range of different subjects. At this point we will simply list them. 1. The...
The Management of Reflection and the Family of Angles 31
Breaking the Inverse Square Law 38 Polarized Direct Reflection 41 Is It Polarized Reflection or Ordinary Direct Reflection 45 Turning Ordinary Direct Reflection into Capitalizing on Diffuse Reflection 51 The Success and Failure of the General Rule 55 Doing the Impossible 59 Using Diffuse Reflection and Shadow to Reveal Texture 62 Capitalizing on Direct Reflection 65 Try a Lens Polarizing Filter 70 Distortion as a Clue to Depth 82 Large Lights versus Small Lights 86 Adding Depth to the...
Chapte
Light The Raw Material of Photography How the Subject Affects the Lighting
Fil Hunter Steve Biver Paul Fuqua
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