Water Caustics Effect
Water caustics effect for photos and video: rippling threads of sunlight from a pool or shallow sea, with the picture wobbling underneath. Loops for video.
What are water caustics?
Caustics are the bright, shifting lines you see on the bottom of a pool on a sunny day. The water's surface is never flat, so each little wave works like a lens. It gathers sunlight into thin bright threads in some places and leaves darker patches between them, and as the surface moves, the net of light crawls and reforms.
The effect draws that net over your picture and also bends the picture a little, the way the floor of a pool seems to wobble when you look at it through the water.
The presets and sliders
Pool is the default: Scale 2, a pale blue light and a gentle bend. Shallows makes the ripples finer and brighter, like a sandy beach in a hand's depth of water. Deep makes them large and dim with a stronger bend, and Golden turns the light warm for late afternoon. Still water sets Speed to 0 for a single frozen moment.
Scale sets how fine the ripples are, Refraction how much the picture underneath bends, and Highlights how bright the threads get. Layering adds a second, finer set of ripples on top, which is what makes real caustics look busy rather than regular. Seed picks a different stretch of water.
How to make it look real
Caustics look best on a picture that could plausibly be under water or beside it: a swimmer, a tiled floor, a face lit from below. Keep Highlights low, around 0.4, on a bright photo, or the threads wash it out. On a dark one they can go up to 1 and carry the whole image.
Match the color of the light to the scene. A cool tint suits a pool, and the Golden preset suits a warm sunset. Bloom Effect on top makes the brightest threads glow a little, as they do on camera.
Does the water loop for a video or GIF?
The movement runs on the clip's clock, so the same frame always comes out the same, and a preview matches its export. Speed 0.5, the default, is a slow lapping, and 1 or more turns it into choppy water. For a GIF, keep the loop short and Scale higher, since fine detail makes the file grow.