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How to use a green screen: a step-by-step guide for TikTok and Reels
A green screen (chroma key) swaps a solid color for any image or video. Done well, it puts you in a studio, a stadium or a Cartagena street without leaving your room. This guide covers the whole process, from hanging the fabric to exporting a vertical video.
What you need
- Green fabric, poster board or a flat green wall (or blue if you'll wear green), without deep wrinkles.
- Light: one soft source for your face and, if possible, another to light the green evenly.
- Your phone on a tripod or propped at eye level, in portrait orientation.
- A vertical 1080x1920 background, like the CromaKit ones, and a chroma key app.
Step by step
- Hang the green behind you and pull it as tight as you can; wrinkles create shadows that chroma key struggles with.
- Stand one to two meters in front of the green. This cuts shadows and green spill on your skin and clothes.
- Light the green first, evenly, then light your face with soft light from the front or slightly to the side.
- Lock exposure and focus on your phone camera so they don't shift while you move.
- Record a short test, apply chroma key in your app and check edges, hair and hands.
- Pick a background whose light and perspective match your shot, and add the kit's overlay if it has one.
- Export vertical 1080x1920 and post to TikTok or Reels.
Lighting tips and common mistakes
- Dark patches on the green mean holes in the key. Light the background before you light yourself.
- Strong backlight (a window behind you) blends your outline into the background.
- Avoid green clothes, very shiny jewelry and glasses that reflect light.
- A green fringe around your body means you're too close to the screen or too much light is bouncing off it.
- Keep color temperature consistent: warm light with warm backgrounds, cool light with cool ones.
Kits to practice with
Works with any chroma key app: Green Screen Live, CapCut, VN and more.
FAQ
Can I use a blue screen instead of green?
Yes. Blue works the same way and is better if you're wearing green. Green is usually easier to light evenly for phone cameras.
Why does my key have rough edges or holes?
It's almost always lighting: the green is unevenly lit or you're backlit. Light the background evenly and step away from it.
Which app should I use for chroma key?
Any app with chroma key: Green Screen Live on iPhone and iPad, CapCut, VN, or the TikTok and Instagram green screen effects.
Do CromaKit backgrounds cost anything?
No. Every kit includes a free original 1080x1920 background for your videos, and some include a transparent PNG overlay.
Another guide: Green screen backgrounds for TikTok (free, vertical)