THE SCALE OF REDDENING FOR CLASSICAL CEPHEID VARIABLES

Field reddenings are summarized for 68 Cepheids and used for comparison with other published reddening scales: from reddening-independent indices, photometry on the Lick six-color system, Stromgren system, Walraven system, Washington system, Cape BVI system, DDO system, and Geneva system, IRSB studies, and Cepheid spectroscopy, old and new. Reddenings from period-color relations are least reliable; photometric color excesses vary in precision, accuracy depending on methodology and calibration sample. The accuracy and precision of published Cepheid reddening scales are revealed, leading to a new system of standardized reddenings for 198 variables, of average uncertainty +/- 0.028 in EB-V and precision less than +/- 0.01 for many. The color excesses are used to map the dependence of intrinsic color on pulsation period, the results contradicting ideas about the period dependence of dispersion in Cepheid effective temperatures.