The photometric properties of the surface of Io were investigated at high spatial resolution by a choice of 220 sample regions from the four-color, 8 km/line pair resolution photomosaic of Io taken by Voyager 1. The mosaic logitudinal coverage extends from ~200 ¿W to 350 ¿W (phase angle ~10.5¿.) The regions were categorized on the basis of their visual color in the color print. Categories include: white, yellow, orange, red, brown (polar), and black regions. The photometrically corrected data were plotted as a function of intensity versus photometric angles for each of the color regions in all four filters (orange, blue, violet, UV) using a Minnaert function. The plots of these color regions show large scatter about the least squares fitted lines. The large scatter, particularly for the darker regions, indicates a continuous distribution of albedos on Io and gives evidence of compositional mixing. In all cases, limb-darkening coefficients with useful error bounds (e.g., error <0.2) are found only for the white (k = 0.6¿0.1) and brown (k = 0.8¿0.1) regions. The larger coefficient found for the brown regions is biased upward due to polar darkening. Computed values of the limb darkening do not change significantly among filters. Color ratio plots of the reflectances for each of the regions were constructed (UV/blue and violet/blue versus orange/blue). The distributions of ratios of the various color regions are compared to laboratory measurements of solid SO2 (Nash et al., 1980) and various allotropes of sulfur (from J. Veverka and J. Gradie, unpublished data, 1979). These comparsions indicate that SO2 is the major component (photometrically) of the 'white' regions. Red and white sulfur are seen as variable components of these regions. Color ratios of 'brown' regions suggest a mixture of white and red sulfur. A significant portion of the 'brown' regions have color ratios near those of pure white sulfur. A component of SO2 is found for all 'brown' regions and appears to be latitude dependent. Red regions appear well described by a mixture of red and orange sulfur.