Abstract: A web processor includes a support for supporting a movable web to form a concave trough along a path having a longitudinal axis. A rotatable element is provided which includes a beam redirecting device for redirecting an incident beam of radiation to produce a resultant beam directed substantially orthogonally to the axis of rotation of the rotatable element. The rotatable element includes at least one lens for focussing the resultant beam to produce a focus point on the path. The path is configured such that rotation of the rotatable element locates the focus point on a line non-parallel to the longitudinal axis of the concave trough. In a method for treating a web, a movable web is formed into a concave trough having a longitudinal axis. An incident beam of radiation is directed to a beam redirecting device on a rotatable element to produce a resultant beam of radiation directed substantially orthogonally to an axis of rotation of the rotatable element.