Figure 16.10

This image has suffered a little too much correction, resulting in the posterization of some of its tones.

Brightening Dark Video

Good lighting is often all it takes to make the difference between bad lighting and good lighting. Unfortunately, good lighting isn’t always naturally available, and good artificial lighting is very expensive and requires a skilled crew. For either of these reasons, you will, at times, find yourself shooting in low light. Whether it’s a concert venue, a night shot, or simply a budgetary reality, low-light footage is something you might need to correct when you start editing.

Fortunately, HD cameras are pretty exceptional at shooting in low light. Because digital image sensors are incredibly light sensitive, your camera can capture details that even your eye might not be able to see. However, you might have to coax this detail out of your footage.

We shot the footage in Figure 16.11 at sunset. The shot on the left was shot during the golden hour, and we liked the look, but the shot on the right was shot after sunset and the light was fading fast. Not only is it dark, but it also doesn’t match the other shots in the scene.

356 The Digital Filmmaking Handbook, 4E

Figure 16.11

These shots don’t match due to quickly fading daylight conditions during the shoot. (See also Color Plate 25.)

Most image editing applications come with several different luminance control filters. In Adobe Premiere Pro, the Fast Color Corrector filter has an Input Levels slider that works very similarly to the Levels controls in Photoshop. The center (gray) slider adjusts the gamma. The great thing about a gamma control is that it lets you brighten the mid-tones of your image without lightening the blacks. This is ideal for dark footage, as it allows you to brighten the image without washing out the shadow tones. The black slider lets you set the black level, and the white slider lets you set the white level (see Figure 16.12).

Use the Waveform Display

Look at the waveform display as you adjust the black-and-white levels. The black levels should fall around 7.5 IRE, and the white levels should max out at 100 IRE.

Another way to achieve a similar effect is to use the Brightness/Contrast filter. Increasing the Brightness is similar to increasing the exposure—it makes the whole image lighter. You can then adjust the Contrast to get better black-and-white levels.

You can see our original image in Figure 16.13 on the left and the image corrected this way on the right. As you can see, the waveform on the corrected images shows a much healthier range from black to white.

If you look at the Color Plates, however, you’ll see that the image is brighter, but it’s not that great looking (Color Plate 26). The colors are dull, and it doesn’t match the other shots from the scene. We added the Color Balance filter and increased the reds and greens and decreased the blues to create a more saturated image that favors the reddish-yellow sunset colors in the other shots (see Color Plate 27).

The original shot was quite dark, and it doesn’t appear to have much color in it, so this image also serves as a good example of how well HD footage can respond to color correction even though it’s underexposed.

358 The Digital Filmmaking Handbook, 4E

Figure 16.13

The waveform of the corrected image on the lower right shows a healthy range from black to white (see Color Plate 26).

Compensating for Overexposure

Digital video is very good at handling low-light situations, and it can hold a lot of information in dark areas—information that isn’t visible to the eye but can be pulled out during color correction. Unfortunately, the opposite is true with overexposed digital video. Areas of overexposure that show a loss of detail suffer from a problem that isn’t fixable—clipping. Just as digital audio that goes above a certain level gets clipped, digital video that goes above a certain white level also gets clipped. So the white overexposed areas you see in an image like the one in Figure 16.14 simply contain no information. You can pull down the brightness and make other corrections, and they will improve other parts of the image, but the clipped areas will stay the same—white.