Abstract: An electrostatic powder coating installation is disclosed, incorporating a spray booth in which there are arranged electrostatically charged powder spraying means whereby the powder spray means may apply a coating of said powder to an article. One portion of the internal walls of the spray booth is provided with a filter which is movable through the booth to a cleaning position outside the booth. The movable filter is arranged within the booth so that one face thereof is exposed to the interior of the booth and the opposite face thereof confronts the intake side of a suction device which is effective through the filter to maintain a slightly negative pressure within the booth. The overspray of powder directed at the article will therefore be attracted to and deposited on the exposed face of the movable filter.