  Recent experiments have shown that colloidal crystals confined to weakly
curved capillary bridges introduce groups of dislocations organized into
`pleats' as means to relieve the stress caused by the Gaussian curvature of the
surface. We consider the onset of this curvature-screening mechanism, by
examining the energetics of isolated dislocations and interstitials on
capillary bridges with free boundaries. The boundary provides an essential
contribution to the problem, akin to a background charge that "neutralizes" the
unbalanced integrated curvature of the surface. This makes it favorable for
topologically neutral dislocations and groups of dislocations - rather than
topologically charged disclinations and scars - to relieve the stress caused by
the unbalanced gaussian curvature of the surface. This effect applies to any
crystal on a surface with non-vanishing integrated Gaussian curvature and
stress-free boundary conditions.
  We corroborate the analytic results by numerically computing the energetics
of a defected lattice of springs confined to surfaces with weak positive and
negative curvature
