Subparhelia are positioned as far below the horizon as the parhelia are above it. Their colour is the same like that of the normal parhelia.
The way how subparhelia form differs from that of the parhelia by the total reflection of sunlight from the lower base face of floating plate-shaped ice crystals. Halos below the horizon can only be observed when there are enough ice crystals below the horizon. Good conditions for this are given in the mountains or on board of a plane.