Shadows are important spatial visual cues of virtual objects in augmented reality(AR). A common sense in us assume that shadow should be darker than its surrounding as it is the result of something obscuring the light source. However, it is difficult to render darker pixels using the current generation of Optical See-Through Display(OST) due to the additive display mechanism. For this reason, perceptual methods are introduced, i.e., by using the negative shadow method but the visibility is limited in brighter scenes. This paper presents a novel method that imbues cast shadows with color to improve the visibility of OST AR shadow. The colors of the colored cast shadows is rendered from perceptually weighted complements of the color captured from the real scene. The color imbued cast shadow method is implemented on OST AR Head Mount Display(HMD) and evaluated in various scenes with respect to visibility and spatial perception.