  The Disk Substructures at High Angular Resolution Project (DSHARP) is the
largest homogeneous high-resolution ($\sim 0.035$ arcsec, or $\sim$ 5 au) disk
continuum imaging survey with ALMA so far. In the coming years, many more disks
will be mapped with ALMA at similar resolution. Interpreting the results in
terms of the properties and quantities of the emitting dusty material is,
however, a very non-trivial task. This is in part due to the uncertainty in the
dust opacities, an uncertainty which is not likely to be resolved any time
soon. It is also partly due to the fact that, as the DSHARP survey has shown,
these disk often contain regions of intermediate to high optical depth, even at
millimeter wavelengths and at relatively large radius in the disk. This makes
the interpretation challenging, in particular if the grains are large and have
a large albedo. On the other hand, the highly structured features seen in the
DSHARP survey, of which strong indications were already seen in earlier
observations, provide a unique opportunity to study the dust growth and
dynamics. To provide continuity within the DSHARP project, its follow-up
projects, and projects by other teams interested in these data, we present here
the methods and opacity choices used within the DSHARP collaboration to link
the measured intensity $I_\nu$ to dust surface density $\Sigma_d$.
