Vibrational Raman lines of hydrogen gas show very small collision broadening. As a result the collision narrowing of the Doppler profile which occurs when the mean-free path of a radiating molecule becomes comparable to the wavelength of the radiation is very easily observed in hydrogen. This paper presents measurements of the narrowing effect and of collision broadening and shift of several vibrational Raman lines in hydrogen and deuterium gas. The results are shown to fall between two simple extreme models for the velocity change in a single collision. A summary of the theoretical treatment of line broadening and narrowing by collisions is included.