DIY Fog Screen for Projection

A fog screen is a thin, flat curtain of cool fog you can project images onto or walk straight through. An ultrasonic mist maker supplies the fog, and a smooth (laminar) airflow sandwiches it between two air streams so it stays flat enough to hold a picture. It's water-only, cool, and safe.

How does a fog screen work?

The screen is a flat sheet of fog held steady by airflow. An ultrasonic mist maker makes a dense, cool fog, which is fed into a slot and pushed out as a thin curtain. On each side of that curtain, smooth laminar air streams travel in the same direction at a matched speed, shielding the fog from turbulence so it forms a stable, near-flat plane. A projector then throws a bright image onto that plane, and because the fog is translucent the picture appears to float in mid-air — and since there's nothing solid, people and objects can pass right through it.

What you need and how to size it

The core parts are an ultrasonic mist maker, a reservoir, a fan or blower to create the laminar air sandwich, a slot or manifold to shape the curtain, and a bright projector. Output is the limiting factor: the bigger the screen, the more fog volume it needs to stay opaque, so match disc count to screen size.

• Small tabletop or single-doorway screen: a 3–5 disc unit (1,500–1,900 mL/hr).
• Medium walk-through or display screen: a 9–12 disc unit (2,500–6,000 mL/hr).
• Large event or stage screen: a 12XL (9,000 mL/hr) or multiple units feeding one manifold.

Keep reservoir water no hotter than 120°F, and run continuously while the screen is in use — the fog dissipates constantly, so the screen only exists while it's being fed. See the interactive DIY build for how the mist-maker parts go together, or spec a unit from our ultrasonic mist maker kits.

Is a fog screen safe?

Yes — it's cool water vapor and light, with no heat, flame, or fog-juice chemicals, so it's safe to walk through and safe around guests. As with any water-and-electricity setup, keep the mist maker's electrical connections dry and plug into a GFCI outlet.

What are the limitations of a fog screen?

A fog screen works best in still indoor air — drafts, open doors, HVAC vents, and fans will break up the flat curtain and blur the image, so it isn't suited to windy outdoor use. Image quality depends on a bright projector and dim ambient light, since the fog is translucent. Output has to match screen size: a small unit can't sustain a large opaque screen. And because it's continuously generated fog, expect some humidity and light surface moisture in the immediate area, so it's best on water-tolerant flooring.

Where are fog screens used?

• Events and trade shows — floating logos and walk-through brand reveals.
• Retail and window displays — projected products that appear to hang in the air.
• Stage and theatre — actors and objects passing through projected imagery.
• Halloween and haunts — ghostly walk-through apparitions and projected effects.
• Museums and attractions — interactive "touchable" projections.

For more cool-fog effects, see our Halloween fog projects and the indoor tornado build.

Build your fog screen

Start by matching a mist maker to your screen size, then add a laminar airflow setup and a bright projector. Browse ultrasonic mist maker kits to spec the fog source.