  We show that subwavelength imaging by negative index materials (NIM), related
to their "soft" electromagnetic response, is very (and non trivially) sensitive
to the surface properties. A minute deviation of dielectric permittivity
epsilon or magnetic permeability mu from the ideal values epsilon = mu = -1 in
thin surface layer(s) results in drastic reduction of the resolution limit of a
NIM slab. There may be a gap in the polariton spectrum and this would allow
establishment of a stationary regime even without losses.
