Color is a fundamental element of design and visual storytelling. Traditionally, artists use it to set the mood for their work, the tone of their voice, and to carry a theme in their craft. In the world of video, color grading is an art form all its own. In the not so distant past, the post-production process of color grading was reserved for expensive edit suites, requiring specific and finite tools. Today, color grading is accessible to any editor and the tools to accomplish it are found in most video editing programs. Color grading can make a drastic change to footage, turning day into night or making a drab shot into a vivid landscape. It can make the backlot look like a location from a world away. It doesn’t need to be bold and loud, and can be a small tweak to footage. Even a subtle color grade can have a profound impact on an audience.[vm_ads:segment_break:1]
Why use color grading?
Color grading allows the video editor to control the image. A video clip conveys more than the content it contains. A varied and intentional color palette in video can inform the audience in a multitude of ways. The mood of a narrative is enhanced by the use of color grading. The Walking Dead on AMC is a great example of this. The series is about a group of people trying to survive a zombie apocalypse. It's a dreary and bleak world. Visually it's emphasized through the use of dark muted tones and the absence of bright colors.
Different locations have different nuances, a varied color palette can bring that out. Color can help orient the audience to the location on screen. Films such as Steven Soderburgh's Traffic rely on the use of color as device to denote location as well as differentiate storylines. There are times when producers finds themselves with a catalog of problematic footage and color correction is incapable of fixing it. When bad footage needs to be used, color grading can rescue it. A color grade masks over the technical issues of the footage, using a crafted appearance that helps sell the story. Video journalism shows often do this with nighttime surveillance footage. Instead of using underexposed grainy footage as is, the editor uses color grading to simulate a look that resembles “night vision” videography.
Each pixel’s color is determined by three channels, a set of data, representing each primary color. All colors are a combination of the three primary colors, not necessarily in equal proportions.
Color Grading Definitions
In order to create stunning color with the tools of post-production, it’s important to understand some basics about color in video, how it works and the terms to define it. This allows an editor to understand the majority of tools used in color grading.
Video utilizes an additive color system. The primary colors of this system are blue, green and red. In an additive color system, different colors are created through varying combinations of the primary colors. Each pixel’s color is determined by three channels, a set of data, representing each primary color. All colors are a combination of the three primary colors, not necessarily in equal proportions. A complete absence of color creates black, while white is the full possible amounts of the three primary colors. Color grading is performed by manipulating ranges of thresholds and tolerances within these channels.
Hue is the pure spectral color that expresses or defines a general range of colors. Simply put, this the general term for a color; such red, purple, blue, orange, etc. It defines a general position of color on the color wheel.
Saturation is the amount of a hue used in defining a specific color. When a color is void of any saturation it is black, white, or a variance of grey. A color that is fully saturated has the maximum amount of hue possible. Partial saturation creates a range of colors, from muted dull tones to rich vibrant colors.
Luminance is the brightness of a color. By itself, it’s gray, ranging from black to white. As part of a specific color, combined with a saturated hue, it creates different tints and shades. Video editing programs use several terms to express luminance. Expressed by itself, luminance is a general reference to the overall luminance values. Different applications breakdown threshold ranges of luminance. The more common terms are shadows, mids, and highlights. It’s easiest to think of these in general ranges with variable tolerances, where each tolerance responsible for a specific range of the luminance. Other terms that are used and mean generally the same thing are pedestal, gamma, and gain, as well as lows, mids, and highs.
Color grading is accomplished by manipulating an image’s RGB channels. This can be difficult because adjusting one color channel affects the other two, so dialing in to a particular hue can be frustrating. There’s also the need to target specific ranges of values as opposed to changing the entirety of a clip. This is why there are different tools built for color grading. Many of these tools have common elements. Regardless of the software, these tools work the same way.
The HSB color selector allows the editor to choose color based on Hue, Saturation, and Brightness. Each of these is represented numerically with the hue being measured in degrees, zero to 360. Saturation and brightness are measured by a percentage of zero to 100. There are two visual fields of an HSB color selector, a gradated tile and a bar representing the color spectrum. The bar has a slider that selects the hue. As the slider moves along the bar, the hue is reflected in the tile. The tile is often a box that is a composite of the saturation and the brightness values. If there’s a set of paired axes, the horizontal axis is generally saturation and the vertical axis represents brightness. A target style cursor may be used to select the saturation and brightness on the tile.
The editor makes aesthetic choices that are decided upon in post-production to create the look that contribute to the overall video.