  We find line emission from the hydrogen- and/or helium-like ions of Ne, O, N
and C in the low and short-on states of Her X-1, using the XMM-Newton
Reflection Grating Spectrometer. The emission line velocity broadening is 200 <
sigma < 500 km/s. Plasma diagnostics with the Ne IX, O VII and N VI He-alpha
lines and the radiative recombination continua of O VII and N VII, indicate the
gas is heated by photoionization. We use spectral models to measure the element
abundance ratios N/O, C/O, and Ne/O, which quantify CNO processing in HZ Her.
Photoexcitation and high-density effects are not differentiated by the measured
He-alpha lines. We set limits on the location, temperature and density of the
line emission region. The narrow emission lines can be attributed to
reprocessing in either an accretion disk atmosphere and corona or on the X-ray
illuminated face of HZ Her. In the main-on state, the bright continuum only
allows the detection of interstellar absorption, plus O VII He-alpha emission
lines with sigma = 3200 +- 700 km/s and complex profiles. Other broad lines may
be present. The broad lines may originate in a region near the pulsar
magnetosphere. Fe L lines are not detected.
