Adjustment layers are a simple way to make something out of nothing. They have the power to tie together an overstuffed timeline of disparate shots, and in the process save an editor a great amount of time.
Adjustment layers are found in many of today’s video editing applications. They first existed in image editing programs such as Adobe’s Photoshop. Adjustment layers proved to be so useful, they were quickly integrated into visual effects and compositing software, such as in Adobe After Effects and other prgrams. As video editing applications grew to have more robust features, they soon landed in editors' timelines. An adjustment layer might appear to be useless to the editor who has never used one. To those who have discovered this wonder of wonders, an adjustment layer is a super simple asset that is capable of many amazing feats.
What are adjustment layers?
In layered multi-track video editing applications, as opposed to nodal compositors, adjustment layers are empty layers placed on a track in the timeline. Left alone, it's an invisible layer, taking up space and crowding the timeline. Adjustment layers function like any other clip in the timeline; properties such as scale, position, and rotation can be changed and animated.
At first glance adjustment layers may appear to be plain and simple assets, but uncloaked, theyÃÂre multifaceted timesavers.
An adjustment layer affects any clip underneath it, including a range of clips that it’s stretched over. Any effect applied to the adjustment layer is applied to the composite image of the layers, or tracks, directly below the adjustment layer. When the adjustment layer ends, so does the effect. While the adjustment layer affects the layers below, it does not have an effect on any layer above it. This is incredibly powerful because it allows the editor to get the results of applying an effect, or a stack of multiple effects, simultaneously to multiple clips while only placing one instance of the desired effect on the adjustment layer.
The ability to have one instance of an effect is incredibly efficient, especially in large projects, because only one adjustment needs to be made to the parameters of that effect as opposed to multiple tweaks on each clip. A bonus timesaver is the rendering time of the finished project. Using adjustment layers speeds up rendering because the renderer first composites the underlying layers into a single image and then looks at the single instance of the effect applied to the adjustment layer as opposed to processing multiple instances of the effect on multiple layers.
One of the most common uses for adjustment layers in video editing applications is to perform color grading. An editor builds a desired look by stacking and adjusting multiple effects on an adjustment layer. The editor is able to stretch the adjustment layer to extend the entire length of a scene containing similar shots and the entire scene is now graded with the same effects. Another way to build a unique look beyond using effects, is to change the adjustment layer's blending mode. This changes the way the effects in the layer interact with the clips below and can make for some truly unique looks.
Using adjustment layers for the color grading allow the editor to sample different looks and compare them side by side. Adjustment layers can be stacked one on top of the other on different tracks in the timeline. This compounds their collective effects based on their layer order. A way to test color grades is to stack two different adjustment layers, one on top of the other, each with a different color grade of effects applied to them. Then reposition one adjustment layer to cover only half of the frame and move the other to cover the remaining portion of the frame, with neither overlapping the other. This way the editor can view, side by side, two different color grades over the span of an entire scene. After deciding which look they like best, the editor deletes the non desired look and repositions the remaining adjustment layer so it now covers the entire frame.
Transitions can be applied to adjustment layers, just as they can to any other asset placed in the timeline. This is useful when an editor is using adjustment layers to perform color grading on a large project with multiple scenes. Two different adjustment layers can be placed in the same track, each applying effects to their respective scene. A transition applied to the two adjustment layers, when timed up with the scene transition, will smoothly change the color grade from one scene into the grade of the other.
Adjustment layers have alpha channels, allowing the editor to change it's opacity or apply a matte to it. Adjusting the opacity of an adjustment layer is a simple way to regulate the amount of an effect being used. At 100 percent, the effect is applied in full, with the opacity dialed down to 50 percent, the effect is rendered to half strength. A matte used with an adjustment layer and effects is capable of creating stunning new looks. A soft, shallow depth of field can be simulated by applying a blur to the adjustment layer and then applying a matte to select the desired region of the composite image to reveal the effect. In this same way a vignette can be created by applying effects that soften and darken the image and then applying a soft-edged subtractive oval matte which is centered on the adjustment layer.
Adobe After Effects
After Effects deserves a special spot in any conversation about adjustment layers. It was one of the first video-oriented applications to incorporate them and they play a significant role in compositing and visual effects. Adjustment layers can be created as individual layers in After Effects and function just the same as they do in any video editing application. Unique to After Effects is the application’s ability to turn any layer, including text or vector objects, into an adjustment layer and affect any layer below it. All the editor needs to do is toggle the adjustment layer switch on that layer. Adjustment layers are useful to compositors because they are often dealing with multiple elements inside the frame. The size of these elements vary and often times they are animated to move throughout the composition. Some effects, when applied, are relative to the layer’s size and center position, not the composition’s. These effects won’t create a unified composite look when applied to multiple elements of varying sizes. The editor is able to achieve a unified look by applying the effect to an adjustment layer as the effect will be rendered across the entire composite image as opposed to the individual elements.
At first glance adjustment layers may appear to be plain and simple assets, but uncloaked, they’re multifaceted timesavers. Their versatility allows the editor to accomplish feats that otherwise seem impossible. Whether the task at hand is color grading or building a unique composite, adjustment layers are more than capable. Time is a commodity in editing and a little bit of it spent on utilizing the power of adjustment layers will pay off with big rewards in the long run.
Building Custom Transitions
A trick employed by editors who create their own custom transitions is to build the transition on an adjustment layer. Editors use a stack of effects and animate their properties to build the transition. One popular transition that isn’t standard on most video editing applications is a blur and bloom. As the footage leads into the cut it starts to blur and its highlights start to bloom, it flares at the edit point and the incoming footage comes into focus as the bloom fades. Editors can easily build this by placing an adjustment layer over the two clips and applying a blur effect to the adjustment layer followed by a bloom or glow effect. To make the transition work, editors zero out the parameters of both effects and places keyframes on those parameters where the transition will start. Editors then place keyframes on the effects at the edit point and adjust the blur and the bloom to achieve the desired look. To finish the transition, the editors place keyframes where they want the transition to end and again zeros out the effects’ parameters. Once the transition is built, they can copy and paste it over any cut in the timeline to achieve a unified look. This trick can be taken a step further by creating a project that only contains adjustment layers of custom-built transitions. When a new transition is built, the transition project is opened and the adjustment layer with the new transition is saved to it. This project can be brought into any new projects and the custom-built transitions are available to copy and paste.
Contributing editor Chris “Ace” Gates is an Emmy Award-winning writer and editor.