Moreover, textured backgrounds that are subtle at true-color (24-bit) settings, often become very noticeable at lower-color settings (i.e., 8-bit), thereby reducing the contrast between the text and the background even further. Thus, if one is to use a textured background, it is recommended to be very careful by testing it in different color settings.
As for color, as long as there is sufficient contrast between the text and the background, many color combinations are possible. However, most studies have shown that dark characters on a light background are superior to light characters on a dark background (when the refresh rate is fairly high). For example, Bauer and Cavonius (1980) found that participants were 26% more accurate in reading text when they read it with dark characters on a light background. Moreover, a survey by Scharff, et al. (1996) revealed that the color combination perceived as being most readable is the traditional black text on white background. However, it is common for websites (such as this one) to have an off-white background in order to reduce the flicker and glare associated with white backgrounds.
In the Scharff et al. (1996) study, other color combinations that ranked high were white on dark blue and red on yellow. However, one should be cautious in using colors such as red on yellow that are pure or 'saturated.' Saturated colors create visual fatigue and make it difficult to focus on the text. It is best to de-saturate colors by adding white or combining them with other colors.
The least readable combination were green on yellow, white on fuchsia, red on green, and fuchsia on blue. Also, for all combinations, the lighter backgrounds with darker text were considered to be more readable than darker backgrounds with lighter text.