Variable blend width compositing

A method of producing an image with a blurred background (151) from an initial image (111) and a depth map (112) identifying a foreground region (236) and a background region (237) of the image, said method comprising determining (670) an edge visibility measure (671) for one edge (231) in the depth map (112) by comparing (820) a pixel value (233) in the foreground with a pixel value (234) in the background, said edge visibility measure (671) distinguishing between the foreground (236) and the background (237); applying (680) a spatially variable blur to the depth map (112) to produce a compositing matte (681), dependent on the edge visibility measure (671); applying (530) a blur to the background region (521) of the depth map (112); and compositing (150) the blurred background image data (531) with the initial image (111) to produce the rendered image with the blurred background (151)