As the military increases its reliance upon and continues to develop Helmet Mounted Displays (HMDs), it is paramount that HMDs are developed that meet the operational needs of the Warfighter. During the development cycle, questions always arise concerning the operational requirements of the HMD. These include questions concerning luminance, contrast, color, resolution, and so on. When color is implemented in HMDs, which are eyes-out, see-through displays, visual perception issues become an increased concern. A major issue with HMDs is their inherent see-through (transparent) property. The result is color in the displayed image combines with color from the outside world, possibly producing a false perception of either one or both images. Last year at this meeting, we discussed the development of a color discrimination model. Here we extend this model to evaluate the discriminability of transparent symbology from a color normal and color deficient observer perspective.