Procedure to estimate the fraction of rMS and bMS stars in NGC 6752 using the V versus c_U,B,I diagram (panels a), b), and c)), and the B versus U − B CMD (panels d), e), and f)). Panels a) and d) reproduce the same diagrams as Figs. 8 and 5. The red line is the rMS fiducial line. Panels b) and e) show the verticalized MS. The histogram distribution of Δ(color) for the stars of the panel b) and e) is plotted in panels c) and f) for three intervals of magnitude. The thick black lines, superimposed to each histogram, are the best-fitting biGaussian functions, whose components are colored red and blue. In the case of V versus c_U,B,I CMD, we found that rMS and bMS contain 77 ± 4% and 23 ± 8% of MS stars in panel c1), 74 ± 5% and 26 ± 8% of MS stars in panel c2) and, 75 ± 5% and 25 ± 8% of the MS stars, respectively. In the case of B versus (U − B) CMD, we found that rMS and bMS contain 72 ± 5% and 28 ± 8% of MS stars in panel f1), 74 ± 6% and 26 ± 9% of MS stars in panel f2), 73 ± 5% and 27 ± 8% of MS stars in panel f3), respectively.