  The superimposed pair of spiral galaxies NGC 3314 offers a unique opportunity
to trace the dust properties in a spiral galaxy. We analyze multicolor HST
imaging, supported by ground-based near-IR imaging and fiber-array spectroscopy
to measure dust extinction in the foreground Sc galaxy NGC 3314A, which is
backlit by the Sb system NGC 3314B. We can measure extinctions over a wide
range of galactocentric radii in the foreground galaxy, from 0.4-4.5 kpc. In
the outer disk, the extinction is strongly localized in discrete dust lanes.
These dust features show an extinction curve with a slope close to the Galactic
mean (R = 3.5+/-0.3) from 1.6 to 3.8 kpc, with no radial trend. Using the I-K
color of the background nucleus, we derive an extinction A(I) = 3.3 through the
disk at a projected distance 400 pc from the nucleus of NGC 3314A. The
extinction in even the inner disk of NGC 3314A is quite patchy, since
background H-alpha emission is detected from all parts of the system. Local
anticorrelations between foreground and background line emission demonstrate
that the dust is concentrated to star-forming regions, as has been found for
the blue light in several systems. Colors of dust lanes in NGC 3314A which are
projected only partially against the background disk indicate that the dust
scale height in the foreground disk is substantially smaller than that of the
stars.
