Light Painting Camera

A phone cannot hold its shutter open for a minute. This app fakes it, and what comes out is a real long exposure.

The camera streams frames and blends every one of them into a single image you watch build up on screen. Walk a torch through a dark room and the line it draws stays there. Close the shutter and that image is your photo.

WHAT YOU NEED
A dark room, a phone you can lean on something, and any small light. A torch, a bike light, a phone screen, a sparkler. That is the whole kit.

FIVE WAYS TO BLEND
Light trails. The brightest pixel of every frame wins, so streaks stay and the dark stays dark. This is the classic light painting look.
Comet. Trails decay as they age, so the light keeps a tail behind it instead of closing a loop.
Glow. Light builds up instead of just winning. Go over the same spot twice and it gets brighter, which is what painting a surface with light needs.
Smooth. Frames averaged, like a slow shutter. Silky water, soft crowds, clean traffic.
Dark trails. The darkest pixel wins, so you draw with shadow across a lit scene.

BUILT TO GET IT RIGHT IN CAMERA
Exposure lock freezes brightness, white balance and focus the moment the shutter opens. Without it the camera re-meters on every frame, so waving a light makes the whole scene pulse and the white balance chase your torch. It is the single biggest difference between a clean stack and a muddy one.

Auto black point measures the dark before any light has been painted, so sensor noise cannot stack up into a grey haze over a long exposure.

The viewfinder warns you about the two things that quietly ruin a painting, and neither is visible on a dark screen: the phone moving, and the room being too bright for the blend you picked.

CONTROLS
Bulb, or a timed exposure that saves itself when it reaches the target
Hold and resume mid exposure, or clear the canvas and take it again
Torch, front and back cameras, exposure compensation, dark floor and trail fade
Tap to focus, thirds grid, keep screen awake

READOUTS, IF YOU WANT THEM
ISO, shutter speed, EV, megapixels, a lock badge and a live histogram of the composite, plus frame count and frames per second. Off by default, because a clear screen is the better first run.

RESOLUTION IS A REAL CHOICE, NOT A QUALITY SLIDER
Fluid caps the stream at Full HD and keeps the frame rate high, so a moving light draws one unbroken line. Detail saves at the largest size your camera offers but at far fewer frames a second, so a fast light can come out dotted. The fps readout sits next to the frame count so you can judge it for your own phone and your own scene.

SAVING
Frames go to DCIM/Light Painting, alongside your camera photos, so they turn up in your phone gallery with today's shots instead of filed away in some separate album. JPEG at full quality, or lossless PNG. Every frame carries the time it was taken.

The app keeps its own roll as well, with the blend, exposure length, frame count and resolution behind every shot, and you can view, share or delete any of them from there.

FIRST RUN
A four step guide covers the mistakes everyone makes at the start: expecting a normal camera, shooting with the lights on, holding the phone, and moving the phone instead of the light.

NO ACCOUNT, NO SUBSCRIPTION
No account, no analytics, no subscription. It asks for the camera and nothing else. Everything happens on the phone and nothing is uploaded.