FX looks
Ghost detector apps: what they measure (nothing)
Ghost detector apps are a genre with millions of downloads and no physics behind any of them. That does not make them worthless — it makes them entertainment, which is a different thing.
There is no sensor for this
A phone contains a camera, microphones, an accelerometer, a gyroscope, a magnetometer, a barometer on some models, and radios. None of these has a channel through which a ghost could arrive, because there is no measured phenomenon to build such a channel around.
The apps that show readings, radar blips and word lists are generating them. The magnetometer ones do pick up real magnetic fluctuation — from the steel in the wall, the wiring behind it and the phone's own speaker — and label it paranormal. The word generators pick from a built-in list; your brain supplies the meaning, which is exactly why it feels uncanny.
Anyone selling this as detection is selling a random number. We are not going to add one.
What we do have: the ghost look
GHOST is one of the five NIGHT treatments — a cold, smeared, high-contrast grade with heavy grain and a soft trail on movement, the visual language of every piece of "paranormal" footage you have ever seen. It is a camera effect and it is labelled as one.
Made for video
The trailing and grain read best in motion. Record with sound.
Pairs with the HUD
Scan grid and brackets over the picture, for the full found-footage look.
Nineteen other looks
Thermal palettes, night vision, blacklight, x-ray, glitch and more.
Apple Watch shutter
Put the phone somewhere and fire it from across the room.
Questions about the app
- Do ghost detector apps really work?
- No. There is no sensor in a phone that could detect something for which no measurable signal has ever been established. The readings are generated, or they are ordinary magnetic and audio noise relabelled.
- Does Thermal Camera detect anything paranormal?
- No, and it does not claim to. The ghost look is a visual effect on the live camera picture.
- Why does the HUD bracket people, then?
- It uses Apple's on-device Vision framework to find the shape of a person in the frame. It is shape detection, it does not recognise anyone, and the result is discarded with the frame.