Color Correction and Color Grading in Post Production
Color correction is the manipulation of the saturation, luminance and balance of the red, green and blue values of your recorded image. In the days when everything was shot on film, color choices were needed at the beginning of the production process. The Director of Photography (DP) would select film stocks with exposure ratings (ASA) and color temperatures (tungsten or daylight) that matched the shooting environment. A tungsten film stock shot under tungsten lighting would look normal, as would a daylight film stock shot in daylight. A DP could create an overall color cast on set by using a tungsten stock in daylight (creating a blue tint to the recorded image) or by using daylight film under tungsten (resulting in an orange tint).
When the intermediate film print was created, film labs could “push” or “pull” an image to increase or decrease the exposure (luminance) and adjust the strength of the red, green and blue printer lights to change the color balance and enhance or correct the footage that was originally captured on set.
The process of scanning film to create a Digital Intermediate (DI) started popping up in the early 1990s to allow computer generated visual effects (VFX) to be incorporated into film footage. The final images were then printed back to film and cut into the final edit. The high cost to create and store these large digital files limited the DI process to effects shots.
As technology advanced and the cost of computing fell dramatically, so did the cost of the DI process. In 2000, O Brother, Where Art Thou? utilized a digital intermediate for the entire film despite having relatively few VFX shots. Along with advances in computer generated imagery came advances in digital color manipulation. Unlike the film printing process that changed the color of the entire image in broad strokes, digital color correction allowed colorists to only affect the parts of the image they chose, giving them a level of color creativity that was not possible before. With the emergence of digital editing platforms, increased visual effects usage and digital color correction, the DI process became the normal way of doing post by the late 2000s.
With today’s digital video cameras, the color balance (commonly know as white balance) will be set electronically in a camera to match the scene’s lighting prior to rolling. Most commercial and corporate motion media projects are captured digitally, and on set you’ll generally have a client monitor that allows you to get a good idea of what the final image will look like. If you don’t, request one. It’s a great way for the creative team to get on the same page when developing a look for the final piece.
Depending on your capture format, your ability to manipulate the image in post may vary. Most digitally recorded image settings are “baked in” during capture, which can limit your options for dramatic changes in the color suite. This is of little concern if your image is exposed and color balanced properly on set and your creative director isn’t planning to completely change the established look during post.
Some digital cinema cameras now record in a RAW format, which allows for greater flexibility in image manipulation and white balance adjustments during post production (the Arri Alexa and RED Digital Cameras are two examples of RAW cameras). While some cameras may produce great looking imagery right out of the box, shooting RAW means incorporating a color session into your post pipeline is critical.
Bottom line: If you’re looking to create stunning imagery that wows your audience, no matter how your image is captured, a color grading session is a the best way to get the most out of your images.
David Anderson is the CEO of Chimaeric, a motion media storytelling firm. His experience ranges from feature film roles as Director of Photography, Post-production Supervisor and Colorist to producing, directing and editing countless commercials and corporate films. Anderson received his Bachelor’s Degree in Communications from William Woods University and is also a graduate of the New York Film Academy at Universal Studios in Los Angeles, CA.