A computer implemented method of interacting with a three dimensional image based lighting surface to adjust its lighting properties, comprising defining an image plane and a user viewpoint for the lighting surface; rendering and displaying a scene containing an object in situ within the lighting surface; by way of a user interaction with the displayed scene, receiving an identification of a point on the image plane; tracing a ray from the user viewpoint through the identified point on the image plane and either, determining a surface intersection point of the ray with the surface or determining an object intersection point of the ray with the object and tracing a further ray, and determining a surface intersection point of the further ray with the surface, and adjusting the lighting properties of the surface at or in the region of the surface intersection point.