Grain Growth in Azimuthal dust traps: Cycle 2 Observations of HD142527

We discuss techniques to extract spectral trends from ALMA data, and estimate biases in the inferred physical conditions by comparison with simulations on radiative transfer predictions. We apply our diagnostics to recent ALMA datasets, including the radial variations in the HLTau rings, and new Cycle2 low-frequency  continuum observations of the azimuthal dust trap in HD142527.