  We study the presence of reversed polarity magnetic flux in sunspot penumbra.
We applied a new regularized method to deconvolve spectropolarimetric data
observed with the spectropolarimeter SP onboard Hinode. The new regularization
is based on a principal component decomposition of the Stokes profiles. The
resulting Stokes profiles were inverted to infer the magnetic field vector
using SIR. We find, for the first time, reversed polarity fields at the border
of many bright penumbral filaments in the whole penumbra.
