 Visual perceptions are dependent on the interaction of the human visual system with any bi-stable or multi-stable stimuli and the frequency of its occurrence.The lighting of objects at a point, the reflectance of those objects and the transmittance of media between the object and observer is central to determining the primary factors that affect our visual perception.It is due to this that a low contrast image is perceived to be of a higher contrast when placed in front of a grey background.