With the popularization of cell phones, laptops, and tablets, Liquid Crystal Displays (LCDs) have become one of the main types of User Interface (UI) in the modern world. While LCDs are widely used for retrieving text information, the impact of text formatting on the legibility is often overlooked. With the goal of improving recognition efficiency (RE) on LCDs, this paper studies the impact of font-background colors on RE of texts being presented on LCD. For this purpose, difference between font/background color combinations, Primary Color Difference (PCD), is introduced that brings efficient RE assessment under wider spectrum. Accordingly, a testing platform is designed in C#. NET that captures participants response time to different font-background color combination stimuli. Based on the results, black background and green font color outperform other tested colors especially when the PCD is maximized. In correspond to results, Implications for using research outcome in prototype LCDs are suggested.