  We present 1-D non-Local-Thermodynamic-Equilibrium time-dependent
radiative-transfer simulations for supernovae (SNe) of type IIb, Ib, and Ic
that result from the terminal explosion of the mass donor in a close-binary
system. Here, we select three ejecta with a total kinetic energy of ~1.2e51erg,
but characterised by different ejecta masses (2-5Msun), composition, and
chemical mixing. The type IIb/Ib models correspond to the progenitors that have
retained their He-rich shell at the time of explosion. The type Ic model arises
from a progenitor that has lost its helium shell, but retains 0.32Msun of
helium in a CO-rich core of 5.11Msun. We discuss their photometric and
spectroscopic properties during the first 2-3 months after explosion, and
connect these to their progenitor and ejecta properties including chemical
stratification. For these three models, Arnett's rule overestimates the 56Ni
mass by ~50% while the procedure of Katz et al., based on an energy argument,
yields a more reliable estimate. The presence of strong CI lines around 9000A
prior to maximum is an indicator that the pre-SN star was under-abundant in
helium. As noted by others, the 1.08micron feature is a complex blend of CI,
MgII, and HeI lines, which makes the identification of He uncertain in SNe Ibc
unless other HeI lines can be identified. Our models show little scatter in
(V-R) colour 10d after R-band maximum. We also address a number of radiative
transfer properties of SNe Ibc, including the notion of a photosphere, the
inference of a representative ejecta expansion rate, spectrum formation,
blackbody fits and "correction factors".
