Premiere Pro: A Quick Fix for Mixed Ambient Light Sources
When shooting in a location where controlled lighting is out of the question, it can be tricky to find a white balance setting that neutralizes all of the different types of ambient light at play. Even if the foreground looks decent, a sea of off-white hues makes the background appear uneasy and distracting. This is where a bit of color correction magic comes in handy (beyond the basic trick of shifting white balance in post).
HSL Secondary Correction within Lumetri Color
After struggling to find a one-stop solution to this, I found the answer in Premiere Pro's Lumetri Color effect. Lumetri contains a menu for a HSL Secondary correction, which acts as a chroma key that masks a specified range of hue, saturation and luminance in the image and applies a desired adjustment. This means that you can select, for example, all of the darkest tones from all hues of an image and desaturate them to stamp out undesired color noise among the shadows. It's a precise way to tune ranges of colors and tones in a video clip. A similar tool was included in the now-obsolute Three-Way Color Corrector effect, however since the 2017 release of Creative Cloud, the color grading suite within Premiere Pro has vastly improved with multiple features combined into a highly functional Lumetri Color effect.
Make the Grays Gray
In simplest terms, the goal of color correction is to make an image match what you see with your eye (separate from the process of color grading, by which you apply a creative effect for the purpose of storytelling). The most noticeable signs of an off-white balance appear on surfaces that are meant to be white, black or gray. You might notice blacks appearing blue, grays appearing greenish, and whites appearing orange all in the same image, even after a basic white balance effect has been applied. So, these neutral tones are my primary target for this particular color correction trick.
One important thing to note before going this route: the following method works best when it's on an adjustment layer over the timeline, over clips that are already individually corrected for exposure levels. Like the HSL Secondary namesake, this secondary effect is one step beyond a basic layer of curves for contrast and a white balance selection.
Three instances of a Lumetri Color effect with a HSL Secondary correction to desaturate different ranges within an image. See below for notes on this method of secondary color correction.
Desaturate the Shadows: Eliminate dark color noise in the blacks
- Start with a fresh instance of the Lumetri Color effect. This one will be our "Desaturate Shadows" effect.
- Under the HSL Secondary menu, slide the Hue (H) selector to encompass the whole color spectrum. Select the full range of Saturation (S) as well. We do this because the shadow noise we intend to eliminate is present across the color spectrum and of all levels of saturation.
- Select only the darkest tones in the Luminance (L) section, so that the effect only targets extremely dark areas. Drag out the feathering slider and play with the ranges depending on the look of your image.
- In the Correction section of the effect, bring down the Saturation level all the way to 0 if you intend to completely eliminate the darkest colors, or to a different level that better suits the image.
Desaturate the Highlights: Eliminate tinted hot spots on light sources and white walls
Now that we've eliminated some noise in the shadows, we can do the same for highlights. Duplicate the Lumetri Color effect (optionally rename it accordingly) and drag the Luminance selector to the highlights.
If it's necessary to prevent skin tones from becoming desaturated along with other hues, you might want to omit the red-orange range from the hue selector.
Adjust the ranges and feathering as necessary to gray-out the white areas without desaturating desired colors.
Desaturate the Desaturated: Make the slightly gray tones completely gray
- In a third instance of the Lumetri Color effect, make a HSL selection that targets the lowest end of the Saturation spectrum, as well as a wide area of the midtones under Luminance and a desired stretch of the Hue spectrum. (Omit a good area of the hue where skin tones might be present.)
- In the Correction settings, bring the Saturation way down, to taste. I find that bring it all the way down to zero is the way to go, and then tweaking the above HSL sliders for the desired result.
While this final phase creates a more stylized result than the above tweaks, bear in mind that the goal is to simply eliminate off-white hues rather than make subjects appear unnaturally clean. By desaturating the desaturated tones, you can allow for more colorful areas of the image to pop.
By playing around with the above three methods, you can crush shadow noise, flatten the hues on white surfaces, and eliminate the ambiguous off-white tones that can plague an otherwise busy scene. An HSL Secondary correction can make for a quick fix to a scene with seemingly uncontrollable ambient light. Variations of this effect can be helpful to just clean up gray surfaces and bring forward the hues of colorful objects. Used alongside effects for exposure, saturation or white balance, you can create a nice clean image from just about any shooting environment.
Adam Kennedy
Creative Director, Resolution Workshop
Beyond directing, writing, editing and animating, Adam doodles in 3D landscapes, tinkers with electronics and hangs out with his dog named Magnet. He enjoys blending digital techniques in unexpected yet meaningful ways.