Intro to color grading
Do your shot in your films look very flat, or washed out? Do your actors come across looking like they have a bad spray-on tan, or blue tinted skin? Have you ever wondered how some digital films have consistently beautiful colors, look beautifully sculpted, and almost look like they were shot on film stock? The secret to great-looking films is usually achieved by color grading.
Simply put, color grading is the process of creating an overall ‘look’ for your film. Filmmakers use color grading to help convey the emotional tone they would like to convey to their audience, and it can be different for each film. This is why a film noir detective film looks completely different than a science fiction film. Color grading is also used to fix problems or inconsistencies in shots that couldn’t be created properly during production. Sometimes the same shot can look completely different on two different cameras, because of differences in lighting, angles, or even just different types of sensors. Editors or colorists use color grading to change the look in post-production so they match up.
Modern color grading is typically done with the use of digital color correction and color grading software. Some editing suites have basic color grading capabilities built in, but at the professional level, stand-alone color correction software is usually used as it gives the filmmaker the highest level of control. Some of the more popular color suites out there include Adobe’s SpeedGrade, Blackmagic’s Davinci Resolve, and Red Giant’s Magic Bullet Colorista. Each software has its pros and cons depending on your individual needs, workflow, and camera, but all are good options to create a great looking film.
One important step in color grading workflow is bringing the color of your shots to a neutral, balanced look. Shots that are too warm or too cool can be corrected so they appear more natural. Sometimes it’s obvious that a shot is too warm or too cool, but you should typically use the color analysis tool built into the color suite. This will analyze the actual RGB channels (the reds, greens, and blues) in the shadows, mid-tones, and highlights of each shot. The software interfaces often use sliders to adjust these channels and balance them to give you a neutral look. This also gives you a chance to adjust the contrast of the shot. Different types of cameras, sensors, and lighting scenarios can make a shot seem to flat or too contrasty. These can be balanced out to help bring back lost details in the highlights and shadows, and to give the film depth and a more 3-dimensional, sculpted look.
A common challenge for digital filmmakers is that modern digital cameras have a look that is distinctly different than that of traditional film cameras. Many filmmakers create stylized looks through color grading to achieve more of a traditional film cinematic style. One of the biggest distinctions between the looks of digital video and film is the way the medium handles roll off. ‘Roll off’ is what happens when one color transitions to another. In digital video, the differences are most prevalent in bright highlights of shots. When video gets too bright it translates to complete white, with no details in highlights. This is referred to as ‘blowing out’ the highlights. Traditional film stock retains some of the detail in the highlights, giving it a much softer and more natural look.
Color grading software often makes use of film look presents called Look Up Tables, or LUTs. These LUTs digitally mimic the qualities of traditional film stocks. Different film stocks have different characteristics; some are very natural, others may have high contrast, or a bleached or otherwise distinctive look. As a filmmaker, you want to select the LUT that helps you best convey the tone of your film. In the color grading workflow, it’s usually easier to start by first applying the LUT to the shots, and then correcting and grading the color on top of that. This allows you to first select the overall look you want for the film, and then make specific color grading decisions to help tweak the shots to achieve that look.