  We describe our application of broad-band photometric redshift techniques to
faint galaxies in the Hubble Deep Field. To magnitudes AB(8140) < 26, the
accuracy of the photometric redshifts is a few tenths and the reliability of
the photometric redshifts approaches 100%. At fainter magnitudes the effects of
photometric error on the photometric redshifts can be rigorously quantified and
accounted for. We argue that broad-band photometric redshift techniques can be
applied to accurately and reliably estimate redshifts of galaxies that are up
to many magnitudes fainter than the spectroscopic limit.
