Rod signals interact with red-green and blue-yellow perceptual hue dimensions to influence color appearance across the spectrum. Hue-naming studies from our lab have identified at least two rod-mediated mechanisms with different spectral and temporal properties: (1) a "faster" rod influence enhances green relative to red; and (2) a "slower" rod influence enhances short-wavelength red and blue. These two types of rod influence are revealed by a probe-flash paradigm. Irt the present study, we examine the effects of background light level on "faster" and "slower" rod mechanisms. We find both rod influences at higher light levels, but only the "faster" influence at lower light bevels. These data provide additional support for the existence of two types of rod influence on hue that differ from each other in spectral specificity, temporal properties, and light-level dependence. (C) 2000 John Wiley & Sons, Inc. Col Res Appl, 26, S60-S64, 2001.