  Using the excellent observed correlations among various infrared wavebands
with 12 and 60 micron luminosities, we calculate the 2-300 micron spectra of
galaxies as a function of luminosity. We then use 12 micron and 60 micron
galaxy luminosity functions derived from IRAS data, together with recent data
on the redshift evolution of galaxy emissivity, to derive a new, empirically
based IR background spectrum from stellar and dust emission in galaxies. Our
best estimate for the IR background is of order 2-3 nW/m^2/sr with a peak
around 200 microns reaching 6-8 nW/m^2/sr. Our empirically derived background
spectrum is fairly flat in the mid-IR, as opposed to spectra based on modeling
with discrete temperatures which exhibit a "valley" in the mid-IR. We also
derive a conservative lower limit to the IR background which is more than a
factor of 2 lower than our derived flux.
