weekly schedule | supplies | readings | downloads | main

PGY 4440C PHOTO COMPUTER IMAGING

CONTROLLING LIGHT FOR PHOTOGRAPHY

Much of life is a dichotomy, isn’t it? Introvert vs. extrovert, liberal vs. conservative, risk-taker vs. risk-avoider, etc.—we have to experience contradictory situations to fully understand the whole. So, too, with photography. Some of us are fascinated by technology—photography’s mechanics; others, by photography’s unique capacity to communicate—its aesthetics.

I tend to be attracted to the latter, but I vividly remember my early frustrations as I acquired the technical skills needed to make understandable visual messages. I was very intolerant of the confusing jargon of tech-nophiles. Of course, with time, my prejudice was tempered, because both aspects of photography have a beauty worth exploring.

While in photo school at Rochester Institute of Technology (R.I.T.) I happened upon an item in an old 1938 issue of Popular Photography saluting the retirement of Edward Steichen. He was then one of the most famous illustrative photographers in the world. The magazine asked him about the biggest problems he had to overcome during his phenomenal photographic career. (It’s important to understand that, sixty years ago, photography was more alchemy than science, and that Steichen’s technical and artistic virtuosity were legendary—one of the gods was about to speak!) I am still impressed with Steichen’s terse reply: “There are only two problems in photography. One is how to conquer light. The other is how to capture a moment of reality just as you release the shutter.”

A few years later, my own photographic career began at Eastman Kodak Company, and I returned to R.I.T. as a part-time instructor. Memories of technical frustrations as a student, as well as on-the-job experiences, helped me think anew about how to explain lighting control clearly and intelligently. I didn’t want to resort to ambiguous terms that required yet more explanation, adjectives such as “soft,” “harsh,” “romantic,” “revealing,” and so forth, or directional effects with names like “Rembrandt,” “Broad,” “Narrow,” “Glamour”, etc. Not only did this verbal complexity require explanation, but many learned technicians didn’t even agree as to what the terms meant! Magazines and textbooks of the day presented worthy photos along with pen-and-ink lighting diagrams. This was supposed to tie things together, but it only made matters worse. The three-dimensional subtleties of effective photographic lighting defy explanation by two-dimensional diagrams.

Furthermore, serious students of photography instinctively knew that something important was still missing. That something, I felt, was the dichotomy between technology and aesthetics. Serious students eventually discover answers by trial and error. As an example, Steichen abandoned his lucrative photographic career for more than a year just to concentrate on mastering subtle lighting effects on very simple objects. The skills he gained soon helped propel him to the top rank of his profession.

My teaching at R.I.T. led me to write a textbook on lighting that has been in print since 1979. There have been three different editions under slightly different titles. The current edition, Lighting Techniques for Photographers, published by Amherst Media, Inc. of Buffalo, NY, explores the dichotomy between technology and aesthetics in part by describing six fundamental qualities that define lighting. These six terms apply to all kinds of lighting, whether artificial (electric lamp, electronic flash, candle flame, etc.), or natural (the sun); whether invented from scratch with fancy lights in a studio, or discovered by chance on location; whether employed by artists, photojournalists or advertising illustrators; whether used by professionals or by beginning hobbyists. The six light qualities are: BRIGHTNESS, COLOR, CONTRAST, DIRECTION, and SPECULAR AND DIFFUSE. The latter two may be unfamiliar terms in everyday photography, but I chose them because they, along with the other four, can accurately describe both the light source and the surface being lit. Lighting cannot be adequately explained without considering both of these things.

Once the six qualities are recognized, both verbally and visually, we empower ourselves to exert the most exquisite control over any kind of lighting. Onerous lighting problems can be compartmentalized and more quickly solved. We can select lighting equipment without being mislead by specious marketing claims. The six terms are simple, easily memorized, and self-evident. Most importantly, when others use these words properly we understand what they’re talking about. There is less room for ambiguity.

Figures 1a, 1b. (Top pair) Specular quality vs. Diffuse quality. The only difference between these two photos is the size of the light source, seen reflected in the silver ball left of pitcher. Figure 1a is specular because it’s from a tiny source. Note that hardedged shadows create light patterns as vivid as the objects in the scene. Figure 1b is diffuse because it’s from a very big source. Note that edges be-tween light and shade can’t be defined, so visual emphasis here is on the actual form and texture of objects in the scene. Both of these examples have a 16:1 light ratio, producing a very high total contrast.
Figures 2a, 2b. (Middle pair) Total contrast and local contrast. Total or overall contrast is mostly altered by light ratio—brightness difference between light and shade—and by the photographic process, for instance with development and paper contrast grade. Local contrast is mostly altered by the light’s direction, and its specular or diffuse nature. Figure 1a is high total and low local contrast—strong blacks and whites but few midtones. Visual emphasis is on pattern. Figure 2b is low total and high local contrast—no vivid blacks or whites but vigorous mid-tone separation. Visual emphasis is on form and texture.
Figures 3a, 3b. (Bottom pair) High and low brightness key. The threadlike weeds and clouds is a high-key photo—it contains no tones darker in value than middle gray. The natural corsage of yellow wildflowers against dark rock is a low-key photo—almost all its tones are darker than middle-gray. Brightness key can influence how we feel about a photo, in much the same way we respond to a preponderance of high- or low-pitched sounds in a musical score.

The Six Qualities of Light

Brightness
The brightness quality of real scenes and objects are seldom duplicated literally on film, even a transparency. Photography interprets brightness. For this reason, the overall brightness quality of any photograph is seldom an exact thing. We experience this as anxiety in the darkroom when trying to make a “perfectly” exposed print. When using slide film, many of us will bracket exposures by half a stop because we want the option of making the “perfect” brightness selection later, during editing. Light meters, even the automatic ones in sophisticated cameras, don’t guarantee exact brightness quality results all the time. The fussiest among us always want to tweak brightness quality to suit our own individual taste.

Visual emphasis can be altered by making parts of the scene lighter or darker—this is local brightness control. Local control can be exerted in so many ways that there isn’t space to list them all, but a few examples suggest lots of others. Dodging and burning when making a print is something everyone seems to do instinctively. Fill-in flash, automatically available on many cameras, lightens nearby dark shadows to show better detail. Studio photographers regularly use shading screens to darken the unwanted visual influences of extraneous objects in a scene.

And many of us are unaware of the elaborate tricks professionals use to make advertisements look dazzling. My son is an automotive engineer, and last year he gave me an entertaining book called Boulevard Photographic: The Art of Automobile Advertising, by Jim Williams. After World War II, long before our age of electronic digital enhancement, it was the lighting ingenuity of the Detroit photo studio of Jimmy Northmore and Mickey McGuire, using local brightness controls especially, that took auto advertising away from artists and their airbrushes. This book is packed with pictures—mostly done on 8x10 Ektachrome film—of cars that glow like jewels, along with explanations of the technical tricks used to make them and many humorous anecdotes.

Another aspect of brightness quality is brightness key. A so-called “high-key” scene (comprising mostly white or light tones or colors) conveys emotional feelings of fragility, gaiety and cleanliness; “low-key” scenes (mostly dark tones or colors) project strength, somberness, and profundity. To obtain a given key, special attention must be given to the subject being lit, as well as to the lighting. For example, if a baby is wearing a dark outfit instead of a light one, a high key photo can’t be achieved.

Color
The bad news about color is that, as a light quality, it’s extremely complex. The good news is that we are really faced with only two technical choices: do we want to control for color neutrality, or do we want to control for color effect?

Color neutrality is almost a given these days because the tight manufacturing tolerances in film and equipment routinely generate pleasing results. But, when photographers want to match the colors in a photo to reality with great accuracy—such as product photos in sales catalogs—then they can become extremely fussy. Here, the only solution is sophisticated knowledge about how subtle changes in the six primary photographic colors—red, green, blue, cyan, magenta and yellow—adjust for optimum neutrality. Those of you who have done color printing also know that manipulation of only two of the colors, magenta and yellow, can provide exquisitely precise control. Additional elaboration about neutrality is not feasible here because the options are almost endless. However, control of color effects can be noted. These are achieved by using solid or gradient color filters over the camera lens, or by putting colored gels on photographic lights. In both cases, the effects are usually self-evident to the eye, and thus, best controlled by simply observing the effects.

Contrast
Contrast quality might be confused with brightness quality because both can be manipulated for visual emphasis. If you follow my explanation, I think you will fully understand the difference between the two qualities.

Contrast is the rate of change between the brightness of light and the brightness of shade in a scene, or between the tones in a photograph. A photo containing only black or white is a maximum contrast situation—the rate of tonal change would be diagramed as a cliff, not as a slope.

However, contrast quality always includes two aspects at the same time: total contrast and local contrast. In the example just given, there is maximum total contrast, but minimum local contrast—the blacks are flat black, the whites are uniform white. To in-crease local contrast we must add tonal changes to the local areas. This is primarily handled by controlling three other light qualities: direction, specularity, and diffusion. Hang on; don’t get confused by all this! I’ll get us back to local contrast control later, and you’ll perceive ways to control light that other technical discourses on lighting control often don’t mention.

Now I’d like to examine what can be accomplished with just one studio-type light. (On-camera flash can be handy, but doesn’t have the versatility of a studio light.) Using just one light is economical and can be entirely satisfactory for a wide range of effects. One studio light, flash or tungsten, with simple modifications, can produce all the variations in the six fundamental qualities of light. However, many photographers avoid buying studio-type lighting equipment because they feel it’s just the beginning of too many added expenses. I hope this article shows that this isn’t the case.

Equipment
While a studio-type electronic flash unit has the advantage of producing a big punch of dependable, daylight-balanced light, even modest units are much more expensive than a tungsten source. Additionally, a flash meter is required and Polaroid film tests are almost unavoidable if you want to see what the lighting looks like in advance. This poses no financial problem for a pro, but it’s a sizeable investment for those with more limited means. This article will emphasize what you can do using using an economical 500–750W tungsten-halogen (quartz) mini-light. Tungsten-halogen illumination consistency is far greater than short-life photo floods you may have used years ago. Most large camera stores carry them. With their continuous-burning illumination, what you see is what you get—no Polaroid is needed; and your in-camera light meter can be used to determine the exposure.

The Lowell Tota-light is one such mini-light. Smith-Victor makes one too; they call it (odd-ly) a Broad Light. With light stand, umbrella and a few accessories, the total package costs about $300—about a third of the cost of the cheapest, entry-level studio-type electronic flash power pack, lamp unit, stand, flash meter and necessary accessories. I like the Tota-light because it accepts an umbrella directly without a separate swivel umbrella adapter.

Total light
The tiny Tota-light—with its protective gull wings open as its reflector—has an ex-tremely specular quality. Attaching an 8X12-inch reflecting panel reduces this specularity somewhat. Shining the Tota-light through, or bouncing it off, a white, translucent umbrella transforms it into an extremely versatile medium-diffuse source. And bouncing the tiny Tota-light off white walls or ceilings produces extremely diffuse illumination. With today’s sensitive films and a 750W lamp in the mini-light, you can use modestly high shutter speeds with a 35mm camera. When taking portraits, for example, there’s no need to ask the subject to “hold steady”; 1/30 to 1/125 sec. exposures are entirely feasible. Inexpensive blue gels also are available to bring the 3200K mini-light color balance very close to that of daylight. Because they are so light-weight, portable and versatile, many photographers, even pros, pack a mini-light in their kit at all times.

(Samples—The Five Extreme Direction Influences)

How can one light be so satisfactory?
Philippe Halsman produced more than 100 LIFE magazine covers during his remarkable photographic career. In 1958, he wrote a book feature for Popular Photography mag-azine called “Psychological Portraiture.” It remains one of the most insightful articles ever written about photographing people. He stated some of his views about controlling light, noting: “I started by buying one floodlight, and by making all my portraits with that alone.” He described its effects on the face when direction and specular/diffuse characteristics were altered, and then added, “I realized, however, that one light limited my photography. The shadows were often too strong and my pictures too dramatic and harsh. Nevertheless, I still use one light in many of my portraits. It has an unusual force and it translates the three-dimensional forms of my subject with an extraordinary plasticity.” Halsman’s simple instruction was an epiphany for me. I’d recently graduated, stuffed full of technical insights but mentally muscle-bound when it came to dealing with the everyday demands of the real world. His clarity was a liberating influence.

However, it should be noted that 41 years ago films were more contrasty than today, and a greater need existed for introducing a second, “active” fill-light. Today, rather than having us get bent out of shape by details of what a fill-light must do, I’ll replace that term with a different one: ambient light. Ambient light exists as stray illumination in most lighting environments; it prevents shadows from going totally black. No matter how forcefully direct a single source may be, there is almost always some scattering to illuminate the shadows. The enveloping sky, for example, scatters direct sunlight to produce lots of ambient light. Artificial light indoors bounces off ceiling and walls to generate ambient light. An exception to these common examples would be a powerful, distant spotlight in a huge, darkened theater. Thus, when using one light for photo- graphy, the technical need for controlling fill illumination depends mostly on the limits of your chosen film to fully record what your eye feels necessary. This is best learned by experience, but today’s films come much closer to recording the full range of tones our eyes readily perceive. I will note ways to increase or modify ambient light, but will not introduce technical trivia about precisely controlling a secondary, “active” fill-light—a tiresome mental exercise that saps creative energy.

One light’s effects on the human face
The examples shown here were lit by a moderately diffuse light source. In this case, light was directed through a 36-inch white translucent umbrella with very low levels of ambient light—they were made in a large, dark- walled studio. With no nearby reflecting surfaces to illuminate the shadows, these examples depict the plasticity that Halsman wrote about, and show shadow effects with maximum clarity. Since the human face is so familiar, these are good examples for predicting how light direction changes might appear on other three-dimensional subjects.

When we observe lighting’s effects, not just the object itself, we have different emotional reactions. Note that each of the five extreme direction influences on the face has its own “feel.” Both 90° downward and upward directions are disturbing. In the downward extreme, where the eyes are shaded and the skull strongly revealed, we sense a lifeless mask. In the upward extreme we sense an unnatural distortion of form that evokes provocative mystery, because natural light doesn’t come from below. The 90° from-one-side extreme cuts the face exactly in half, an explicit division that’s pictorially unsatisfying. The 0° full-front extreme produces the greatest brightness on the subject with no shadows; the only tonal changes occur because of color contrasts in eyes, hair and lips, and because light reflects back with subtly different intensities off the various planes and surfaces of the face. The full-front extreme is a flattering direction influence. Nearly all female head shots for fashion and cosmetic illustrations employ this honey-smooth illumination. The fifth extreme direction influence, a full silhouette of the head, reveals only shape and outline.

Now, if we split the five extreme directions into six points of the compass—all from 45° above the camera, and from both front and back, left and right—we get many more useful lighting situations. The three frontal direction influences typically are used in studio portraiture; the three rearward influences are extremely useful too, but only if there’s lots of ambient light filling in the shadows.

(Samples—Six Intermediate Direction Influences)

Controlling ambient light
Ambient light, by definition, has no direction influence: reflected and scattered illumination from all directions lightens shadows as air fills a vacuum. The simplest way to increase ambient light is to introduce a large, white reflector. During my career I always kept a 4X6-foot, folded, canvas-weight white sheet in my camera bag. Later, I also carried one of the ingenious, spring-actuated fabric disc reflectors that collapse into a convenient carrying size. The shadow-lightening effect such a reflector produces is not dramatic to the eye. It doesn’t have to be, because pictorial nuances like eye catchlights and the addition of a subtle extra glow to small areas in the scene are emotionally satisfying. Ambient light can also be increased by the omnidirectional influence of any additional light bouncing off ceiling and walls. One example: bouncing a mini electronic flash to create added ambient light while the camera’s exposure meter is automatically set to adjust for the existing light in a room is a nifty lighting solution that was agonizingly difficult to calculate only a few years ago.

Reflecting ambient light into a scene can be overdone. Using an aluminized reflector to blast full sunshine into shadows is grossly excessive. The direct, specular light from a flashlight functionally illuminates a shaded work area too, but its stark effect doesn’t qualify as ambient light either. These examples help explain why using a secondary, “active” fill-light tends to be emotionally unsatisfactory—its intrusion can be much too obvious.

Ambient light can be enhanced by simply exposing for the shadows and letting the narrow, directly illuminated areas get way over-exposed. This is a handy lighting technique, especially when the background is also in shadow. The result is attention-getting with lots of pictorial sparkle. Sports action—baseball, football, tennis—is often done while shooting toward the sun with the shaded side of the stadium as a backdrop. It’s essential to use an efficient lens shade. (A 300mm lens should have a tubular lens shade at least eight inches long. Stop your lens all the way down, and aim your single lens reflex camera at the bright sky. You’ll be surprised to find no vignetting in the corners of the view-finder. The built-in, slip-out 3-inch lens hood is virtually worthless. With shorter focal length lenses, use a collapsible, rectangular bellows lens shade to exactly crop out unwanted backlight lens flare.)

Copying flat art
Here’s where one light is better, even though many lighting texts routinely describe a formula for using two. One light is cleaner, more flexible, and superior when flat art has dimension. Examples: brush strokes in a painting are best seen under singular illumination; a fan of prints laid across a surface are better rendered with a unifying shadow edge; and textured paper is properly revealed under one light, but not two.

The first thing to understand in one-light-copying is that nearly all spherical light fixture reflectors cast uneven illumination. This is not the problem—it’s the solution, because the light from a spherical reflector can be “feathered.” When the reflector’s brightest core of illumination is cast toward the farthest part of the subject, the effect adjusts for the geometric fall-off in brightness. Even when the distance across a surface is small, feathering always produces more even illumination across the entire surface. To make the illumination perfectly even, place a white reflector near the far edge of the art to introduce some ambient light. The tonal subtleties I’ve noted are almost imperceptible to the casual eye, but they’re perceptible on film.

Using an umbrella source may be easier for a beginner because its greater diffuse character doesn’t fall off as quickly. Nevertheless, the best results are obtained when it is aimed at the farthest end of the art and a white reflector is positioned near that side.

It takes a little skill and experience to illuminate flat art properly, just as skipping a stone across water or banking a pool ball does. But soon you’ll find yourself able to finesse one light and reflector card with automatic ease, and wonder why you ever agonized over doing it any other way.

The one light should be positioned a good distance away—at least five times the width of the art being copied. This gives you room to work and further minimizes geometric fall-off in illumination. It’s essential that any shiny parts of the camera be invisible to any dark, shiny surfaces on the art. Do not use expensive pola-screens over the lens and light unless the art contains areas of India ink that must be rendered as opaque black (India ink dries in a crystalline manner and picks up scratchy reflections from every obscure direction); just be sure the camera, tripod, cable release—and you!—are in deep shadow. The easiest way to ensure this is to cut a lens peephole in a black card positioned between the camera lens and the art, especially if the art is small and a macro lens must be close in.

Don’t overlook the position of the white reflector! Tip it backwards so its upper edge doesn’t accidentally reflect off some shiny portion of the art. Such reflections are very hard to see through the camera’s lens when wide open for focusing. The only sure check is to lay a mirror over the art and look for possible reflections with the lens stopped down. If in doubt, move the reflector farther away, and tip it back more. Remember, the reflector has only a subtle role anyway.