The paper presents a method to recover high dynamic range (HDR) radiance maps from photographs taken with conventional imaging equipment. The authors use multiple photographs of the same scene with different exposure settings to recover the response function of the imaging process, assuming reciprocity. With this function, they can fuse the multiple photographs into a single HDR radiance map whose pixel values are proportional to the true radiance values in the scene. The method is demonstrated on images acquired with both photochemical and digital imaging processes. The paper discusses the applicability of this work in various areas of computer graphics, including image-based modeling, image compositing, and image processing. It also highlights applications such as synthesizing realistic motion blur and simulating the human visual system's response. The algorithm is based on exploiting the physical property of reciprocity in imaging systems, both photochemical and electronic. The paper includes a detailed description of the algorithm, including the recovery of the film response function and the construction of the HDR radiance map. The results section shows the effectiveness of the method through examples, demonstrating accurate recovery of the response function and the reconstruction of HDR radiance maps. The authors conclude that their method is simple, practical, robust, and accurate, with wide-ranging applications in computer graphics.The paper presents a method to recover high dynamic range (HDR) radiance maps from photographs taken with conventional imaging equipment. The authors use multiple photographs of the same scene with different exposure settings to recover the response function of the imaging process, assuming reciprocity. With this function, they can fuse the multiple photographs into a single HDR radiance map whose pixel values are proportional to the true radiance values in the scene. The method is demonstrated on images acquired with both photochemical and digital imaging processes. The paper discusses the applicability of this work in various areas of computer graphics, including image-based modeling, image compositing, and image processing. It also highlights applications such as synthesizing realistic motion blur and simulating the human visual system's response. The algorithm is based on exploiting the physical property of reciprocity in imaging systems, both photochemical and electronic. The paper includes a detailed description of the algorithm, including the recovery of the film response function and the construction of the HDR radiance map. The results section shows the effectiveness of the method through examples, demonstrating accurate recovery of the response function and the reconstruction of HDR radiance maps. The authors conclude that their method is simple, practical, robust, and accurate, with wide-ranging applications in computer graphics.