  We explore absorbing open-boundary modes in non-Hermitian photonic systems.
The modes have a continuum spectrum in the infinite system-size limit and can
exhibit the non-Hermitian skin effect. In contrast to the conventional
non-Hermitian skin modes under the fixed-end open-boundary condition, the modes
concerned exhibit a strongly size-dependent spectrum that gradually converges
to the non-Bloch-band dispersion. The modes correspond to the poles of the $S$
matrix, and are closely related to the lasing. We demonstrate these properties
in a two-dimensional non-Hermitian photonic crystal with gain having a
point-(pseudo)gap topology.
