How to do a double exposure effect in Unity

We recently launched a new episode of Unity Tips, starring Director Bot! In this one, Director Bot show all you squishy human type beings how to create a double exposure effect in Unity. It’s a really neat looking aesthetic that seems to be gaining a lot of popularity lately, even being featured in that new Apple ad featuring U2, where images of The Ramones are double exposed into the image of Bono.

In analog photography, this sort of effect is done by taking a silhouette-like base image. Nice and contrasty, almost making a matte. So the darker parts in the image, i.e. your subject, will be able to have another image exposed onto them. The brighter parts of the image are already exposed, so they won’t be affected. So you’d rewind your film, take another exposure on the same frame, and you’d get something that looks like this:

And this is pretty cool. With digital technology, we can do this with video as well. It’s the same sort of principal, but instead of rewinding film we can just take the two videos, and composite them on top of each other. This works out pretty well.  You put the silhouette-like image on top of the other image, and set the transfer mode of the silhouette-like image to “Screen.” After some contrast tweaks, you’re done!

In this video tutorial, we accomplish the exact same thing, but all in Unity, step by step. Unity has a script in Image Effects called Screen Overlay, that would almost make this effect really easy to accomplish. Too bad it only lets you overlay still images!

To get around this, we made a new script that lets you link two LIVE cameras together, so you can get the double exposed video effect like we see in the examples. Sweetness! You can get it here. But remember: you’re going to need Unity Pro for this to work.

Be sure to check back for a new Unity Tips soon! Director Bot has plenty more cool things planned.