From a long time, readability formulas have remained favorite and trustworthy in analyzing the readability, however, researches have now made their trust worthiness a bit shaky as they lack usability components in them. In this paper, the readability formulas are analyzed against usability factors. For this purpose, a group of 40 readers belonging to different age groups, gender, educational backgrounds and variant skills, were selected to analyze the effect of color contrast on readability. The readability measures in terms of usability constraints are put on the scrutiny for the validity and effectiveness of the formulas. The usability factors that can be met by emending or modifying the readability formulas are put forth to get the desired success ratio for ease of reading. Among the identified factors, the color contrast of foreground and background is picked and a survey was conducted that ensured the strong effect of color contrast on readability. The color contrast factor is adjusted in the readability formula that resulted better and enhanced readability analysis.