  In the holographic correspondence, subregion duality posits that knowledge of
the mixed state of a finite spacelike region of the boundary theory allows full
reconstruction of a specific region of the bulk, known as the entanglement
wedge. This statement has been proven for local bulk operators. In this paper,
specializing first for simplicity to a Rindler wedge of AdS$_3$, we find that
generic curves within the wedge are in fact not fully reconstructible with
entanglement entropies in the corresponding boundary region, even after using
the most general variant of hole-ography, which was recently shown to suffice
for reconstruction of arbitrary spacelike curves in the Poincare patch. This
limitation is an analog of the familiar phenomenon of entanglement shadows,
which we call 'entanglement shade'. We overcome it by showing that the
information about the nonreconstructible curve segments is encoded in a slight
generalization of the concept of entanglement of purification, whose
holographic dual has been discussed very recently. We introduce the notion of
'differential purification', and demonstrate that, in combination with
differential entropy, it enables the complete reconstruction of all spacelike
curves within an arbitrary entanglement wedge in any 3-dimensional bulk
geometry.
