Desires by customers for color helmet mounted displays (HMD) that are suitable for day and night viewing are being explored by several companies. One major area of difficulty for designers is selecting a shade of blue that is bright enough to be seen and that can be discriminated as blue in a bright ambient environment. Customers have concerns on how rich the color of blue must be to satisfy the pilot, but this may sometimes become a conflicting requirement of discrimination. Rockwell Collins is designing the next generation HMD and believes that color, if not a requirement, will be an expectation in the future. To this end Rockwell Collins has conducted testing on a full color HMD display with a goal of determining the best color blue/cyan for our design. Our goal is to determine the u’v’ coordinates on the CIE chart that meets both goals of brightness and discrimination. Our testing used a fixed wing HMD with a full color, 24 bit, OLED display. Multiple symbols and colors were used during the testing, and subjects were not aware of the goal of the study. It was found during the study that a much brighter blue/cyan can be presented and discriminated from other colors. Our paper will discuss the testing approach, and a summary of data and results. A conclusion is presented at the end of the paper of the HMD design impacts and implications of focusing less on color and more on discrimination.