Quantity or Quality?
Light is confusing. Consider this question: "As a subject gets closer to a light, does the light become harsher or softer?" Think about this for a minute. Imagine you are in a room at night with a single table lamp across the room providing illumination. Hold up your hand. Walk toward the light. Does the amount of light falling on your hand increase? Yep. Sure does. So the closer you move to the light, it gets brighter and harsher. Right? Well, half right, anyway. It does get brighter. It also becomes softer. And we humans, thanks to the way our brains work, universally confuse brightness with harshness. We mix up the quality of light with the quantity we see.
Shadow edge transition
Imagine you are walking away from the light. Hold one finger over the other palm of your hand. It casts a shadow. Look at the edge of the shadow. It sharply outlines the shape of your finger (Figure 4.7). The edge marks the transition from highlight to the shadow. If the shadow has a sharp edge, the light is harsh. Now think of shadows cast on a sunny day. They are very defined. The earlier photographs of Marie as seen in Figures 4.4 and 4.6 are made with harsh light. The edges of the shadows cast by her nose and chin are very sharp.
Now pretend you are walking toward the lamp. As you get closer, notice the edge of the shadow cast by your finger on your palm. The edges of the transition from highlight to shadow are blurred. By the time you get next to the lamp, the shadow and the highlight almost merge. What's going on here? The light is really bright and the shadow edge is soft. Hmmm. Well, there are a couple of things happening.
First, the light has become much larger in relation to the size of the subject so the transition from highlight to shadow is spread out (Figure 4.8). The result is an almost shadowless image similar to what you see on an overcast day in which the whole sky is the (really big) source of light. Second, as the light gets brighter the exposure on the camera has to be lowered to compensate. The background becomes darker.
The larger a light source is in relation to the subject, the softer the quality of the light. Large light sources make soft light. The transition from highlight to shadow is spread over a large distance. Small light sources create harsh light and sharp shadow edges.
Instant soft light
Soft light is great for portraits of women and children. The long shadow edge transition minimizes texture in skin and enlarges the catchlights in the eye. It is very pretty. Best of all, it is easy to achieve. Either wait for an overcast day or slip a diffusion panel in front of the light source. Think of diffusion panels as on-demand clouds or port-a-clouds.
Sunny-day soft light
Outdoor sunlight streaming through tree leaves creates areas of very bright highlights and deep shadows, resulting in a high-contrast scene (Figure 4.9). The sun on Cara's face and legs is so bright that the detail in her skin disappears completely due to overexposure. Closing down the aperture on the camera to compensate would make her outfit go completely black. Look at her black robe draped over the chair. You can see folds in it. The exposure is correct for the shadows because these details show. So how can the contrast be lowered?
Remember that the only way to lower contrast is to add light to the shadows. The solution is to bring in a diffusion panel that is large enough to soften the light falling on Cara. In this case, it's a 42 x 72-inch Chimera frame with a full translucent panel on it (Figure 4.10).
Now the patches of bright sunlight and the shadows cast by the leaves blend into soft light (Figure 4.11). The panel's fabric reduces the amount of light reaching Cara by 1½ f/stops. If we open up the camera's aperture by that amount, the exposure adds light to the shadows, thereby lowering the contrast on Cara. At the same time, the increased exposure brightens the background not covered by the panel by 1½ stops, as well. The light hitting the stone wall behind her is much brighter now, complete with blown-out highlights. Brightening the background in a photograph by reducing the light hitting the subject and then increasing the exposure to compensate is called subtractive contrast control.
Harsh then soft studio light
Any light you find in nature can be duplicated in the studio—and it's not hard to do. In this section, you'll see how to place a single flash to replicate the effects of sunlight on both a clear and an overcast day.
Photographs do much more than tell the story of their subject. They also share exactly how it was lit. (Well, if someone has been playing around in Photoshop, it may not be exactly how the subject was lit.) Learning to read the lighting cues in a photograph goes a long way when you are creating the lighting yourself. Specular highlights reflect the source of light in the subject. Look for them on the hood of a car, on the glass of a window, in the water of a pond or lake, and in the eyes as they catch the light (Figure 4.12).
Specular highlights show you the size of the light shining on the person. A big catchlight reflects a large source and that means a gradual shadow edge transition, the indicator of soft light. A pinpoint of light in the eye would lead you to look for a quick, sharp shadow edge. Sometimes you can uncover retouching done on photographs by examining the catchlights. If the shadow edge transitions don't jibe with the specular highlights, you can be almost certain that Photoshop has touched the photograph. Now that you know how light works, your photographs with long, smooth shadow edges won't have teeny tiny catchlights in the eyes, will they? Of course not.
Harsh light, high contrast
This photograph of Marie is lit with harsh light (Figure 4.13). The tell-tale signs are the sharp transition from dark to light in the shadow cast on her cheek by her nose and on her shoulder by her chin. The tiny catchlight in her eye shows the size of the light source.
The high-contrast harsh-light image is made with a single flash set twenty feet from Marie and positioned forty-five degrees to her left and forty-five degrees above her (Figure 4.14). The flash is both the origin of light and the source of light because there isn't a modifier (such as a diffusion panel) between it and the subject. At twenty feet, the 5½-inch reflector is about the same relative size as the sun.
Here's an easy way to see if your light will deliver sun-like quality. Hold your thumb at arm's length from your eye. If your thumb blots out the light, it will be very close in quality to the sun. I guess this really is a "rule of thumb."
Soft light, low contrast
This photograph shows Marie in soft light with low contrast (Figure 4.15). The shadow edge transition is spread over a wide distance. The change from highlight to shadow is almost undetectable because of the low contrast. Again, the catchlights in Marie's eyes show the size of the source of light.
Three changes have been made—two on the set and one in the camera. Two incident controls—a diffusion panel and a bounce panel—have been added. Incident controls modify light before it reaches the subject. Some other changes have happened by adding the incident controls. The diffusion panel becomes the source of light. The source of light always illuminates the subject. In this setup, the flash is the origin of light. It lights the source. The bounce panel, in this case another Chimera panel covered with silver lame, catches light from the source of light and the origin of light to fill in the shadows, seriously lowering the contrast (Figure 4.16).
Take a closer look at Marie's eyes (Figure 4.17). The silver bounce panel shows on her right, and there is another reflection on the lower part of her iris. The white floor adds even more fill light.
Finally, as in the earlier example diffusing the light outdoors on Cara in Figure 4.11, the exposure on the camera has been increased to compensate for the brightness reduction caused by adding the diffusion panel.
Soft light, high contrast
Removing the bounce panel from the set takes light away from the shadow side of Marie's face and the contrast increases (Figure 4.18). Adding light to the shadows lowers contrast. Removing it from the shadows increases contrast. Contrast, and the quality of light, are all subjective decisions made by the photographer. Once you have set the diffused value (exposure on the camera), everything else is relative to it and under the rule of your every whim.