Tests of broadband photometric consistency for standard stars, the Hyades, and M67

New South African Astronomical Observatory (SAAO) BV(RI)(C) measurements of 19 Hyades stars and 11 M67 stars are reported. The zero points of the new color indices conform closely to those of SAAO data reported in a previous paper. In addition, the new M67 measurements of (V - R)(C) and (R - I)(C) are compared to data published previously by Taylor, Joner, and Jeffery. The results support conclusions drawn by those authors that the scale factors of their data are correct and that a scale factor problem exists in measurements published by Montgomery, Marshall, and Janes. The new values of B - V are used with Tycho data in tests of extant Hyades and M67 measurements and of the accuracy of the SAAO B - V system. A problem encountered previously with the Hyades B - V zero point is resolved, and an extant Hyades relation between B - V and (R - I)(C) is re-zeroed. A satisfactory zero point is also obtained for M67, and published photomultiplier values of B - V are reduced to that zero point, averaged, and tabulated. It is found that the zero point of B - V data published by Sandquist is satisfactory. However, tests of B - V measurements made by Montgomery et al. suggest that those data are not on a single zero point. Finally, the scale factor of the E region B - V system is found to be satisfactory, but a well-supported interim conclusion is drawn that E region values of B - V should be corrected by about - 9 mmag. It is suggested that this conclusion be tested by using instrumental systems that have not yet contributed to the testing process.