The Split Light effect divides your screen into a lit side and a transparent side along a vertical line: the left side fills with your chosen color, the right side is fully transparent. The Split Ratio control moves that line anywhere from 10% to 90% of the screen width. Positioned in front of you, the line becomes a lit-and-shadow boundary across your face or subject — a fast way to get the classic "half light, half dark" portrait look without physical lighting gear.
Before you start
- A screen you can position close and face-on. Split Ratio moves the dividing line between 10% and 90% of the screen width, but landing it precisely on your face still depends on where you sit and how you angle the screen.
- A dim or controllable room. The dark half of the effect is transparent, not a dark color, so it shows whatever is actually behind the screen. Bright room light will fill in that "shadow" side and flatten the contrast you're going for.
- Something dark behind the screen, like a wall or the page background, if you want the transparent half to actually read as dark rather than showing your desktop or another window behind the browser.
Set it up
- Open the Split Light effect on the screen you'll use as your light source.
- Set Color Temperature to the tone you want on the lit half — Tungsten or Warm White for a warm, cinematic split; Daylight or Cool White for a cleaner, neutral look.
- Set Brightness to control how strong that lit half is. Start around 70–80.
- Drag Split Ratio to set how much of the screen is lit versus transparent — 50 splits it evenly, lower values shrink the lit side, higher values grow it.
- Sit or position your subject so the vertical line falls where you want the light-to-shadow transition — centered on the nose for a classic split, or combine an off-center Split Ratio with your seating position for a more subtle wash.
- Select Go Fullscreen so the full split fills the screen with no controls or browser chrome in frame.
- Check your camera preview and fine-tune Split Ratio or your position until the line falls where you want it.
You'll know it worked when you see a sharp vertical line across the screen: solid color on one side, nothing on the other, with your face lit on one side and falling into shadow on the other. Where exactly the line falls depends on your Split Ratio setting.
What each control does
| Control | Range | What it changes |
|---|---|---|
| Brightness | 10–100 | Intensity of the lit (left) side only. The transparent side has no color to dim — this only affects how strong the colored side looks. |
| Color Temperature | Daylight → Tungsten | The color of the lit side, from a clean 6500K white down to a warm 2700K amber. There's no swatch picker for this effect — only the five listed temperatures. |
| Split Ratio | 10–90 | Where the vertical divide falls, as a percentage of the screen width from the left edge. 50 is dead center; lower values shrink the lit side, higher values grow it. |
There is no angle or line-tilt control — the divide is always a vertical line, and Split Ratio only moves it left or right. Fine positioning relative to your face still comes from physically moving the screen or your seat.
Common setups
- Classic dramatic headshot. Dim the room, use Tungsten or Warm White, Brightness 75, and sit centered so the line runs down the middle of your face. One eye lit, one in shadow, is the traditional split-light look.
- Softer version for a video call. Keep some ambient room light on so the transparent half isn't pure black, use Daylight or Neutral for a cleaner tone, and Brightness around 85 so the lit half doesn't look dim next to your room light.
- Off-center accent. Set Split Ratio to 20–30 (or 70–80 for the mirrored version) so only a sliver of the frame is lit or shadowed, instead of an even split — most of you stays lit, with just a hint of contrast for a subtler effect.
- Two-tone background for content. Sit or stand off to one side of frame so the split reads as a background behind you rather than across your face — useful for stylized talking-head thumbnails or stream overlays.
Troubleshooting
The dark half of my face is a flat black hole with no detail. That side is transparent, not dimly lit, so it shows only what's behind the screen. Add a low secondary light — a lamp, a bit of room light, or a second WebLight screen set to a low Brightness — on that side to bring back some detail without erasing the contrast.
The split line isn't lining up with my face. Drag Split Ratio to move the line left or right as a percentage of the screen width — it doesn't have to sit at 50. If it's still not landing where you want relative to your face, move your chair or angle the screen too; Split Ratio changes where the line sits on the screen, not where you're seated relative to it.
The lit half looks washed out or barely colored. High Brightness with a pale temperature like Daylight or Cool White can look close to plain white. Switch to Warm White or Tungsten for a color that reads clearly on camera, then adjust Brightness from there.
My camera shows the desktop or another window instead of solid black on the dark side. The transparent half is rendering exactly what's behind the browser. Go fullscreen so the page itself has nothing behind it but its own black background, and if you're screen sharing, share the specific window or tab rather than your whole desktop.
The edge between light and dark looks blurry on camera. The effect itself has no blur or feathering — it's a hard-edged split. Softness on camera comes from your camera's focus or video compression, not a setting here.
Split Light looks too harsh for a normal video call. That contrast is inherent to the effect — half the frame goes dark. Bring up ambient room light on your shadow side, raise Brightness, or use a less binary effect like Key Light if you want directional light without a hard black half.
Next steps
For directional light that doesn't cut all the way to black, try Key Light. For a focused beam instead of a hard vertical divide, Spotlight offers a different way to concentrate light on one area.