Dry fall paints use additives that allow the paint droplets to dry rapidly, in as little as a ten foot fall. The paint droplets dry to a dust-like consistency which can be swept away. The dry fall capabilities of these paints are temperature and humidity dependent. Low temps and high humidity increases the fall time required for drying.
Dry fall paints are available in acrylic, alkyd and epoxy formulations. Dry fall paint is specially formulated for spray application and is not suitable for application by brush or roller.
Dry fall paint can be another solution to the problem. Using dry fall can allow continued use of spray with less prep time while still keeping sprayed paint out of places you do not want it.
For large outdoor structures, the problem of over-spray with traditional paints can be difficult if not impossible to solve with traditional masking procedures. The paint droplets of standard coatings can be carried for hundreds of feet on the wind, and still be wet when they fall on surfaces. If spraying is still desired, the prep work required to contain the paint adds a significant amount of man-hours to a project.
The usual solution is to change the application, and switch to rollers. Unfortunately, rolling paint over large surfaces is more time-consuming than using spray. So which costs more in man-hours: the prep work for spraying or the application time for rolling?