Normalized absorption profiles of the 3 μm feature toward two background stars published by Boogert et al. (2011) and McClure et al. (2023) and one protostar (Rocha et al. 2025) compared with laboratory ice spectra from Hudgins et al. (1993). The observed profiles (red, blue, and green) were extracted from published data and interpolated onto a common wavelength grid. Laboratory spectra correspond to pure water ice (dotted black) and a strong ice mixture (solid black) at 10 K. All profiles are normalized to a peak optical depth of 1 for a direct comparison of the profile shape.