This paper describes some measurements of the wavelength dependence of characteristic curves for Eastman Kodak IIa-O, IIa-D, and IIa-E emulsions developed in D-19. The variation in the slope of the characteristic curves at density 0.9 above fog was typically 2% per 100 A for all three emulsion types. At a given wavelength, the slope of the characteristic curves typically increased by 4% as the exposure time increased from 0.5-16.0 min. The characteristic curves for different plates taken from the same production batch but not all from the same box reproduced well for a 1-week period. For example, the characteristic curve slopes at density 0.9 above fog had a typical standard deviation from the mean slope of 3-4% at each wavelength.