An apparatus for thermally developing a photothermographic media comprising an enclosed processor, means of transporting a photothermographic element with a latent image thereon to a thermal heating element comprising a curved heating element, which is a rotating cylindrical drum means for placing said photothermographic media with a latent image into contact with said curved heating element, means for heating said photothermographic media with a latent image thereon comprising a heatable curved heating element, and means for removing said media from said curved heating element, said apparatus comprising at least two vents for removing gas from within said processor, said at least two vents being located at least two separate areas within said processor, a first vent being located at a position above the axis of the curved heating element, and a second vent at a position sufficiently near a point on the curved heating element where the photothermographic media is removed from the curved heating element so that at least some vapor material leaving said photothermographic media with a visible image thereon exits through said second vent.