1.5D geometry assumed for the filament and prominence models. An angle-dependent FAL-C semi-empirical chromospheric model plus diffused Planck function is used to construct the wavelength and μ-dependent radiation field input into the filament and prominence stratifications. The prominence case adopts a rotated reference frame to account for the differing projection. Regions comprising the ‘two part’ boundaries are indicated. Coronal illumination is ignored in all cases.