Doctoral robes are typically black, although some schools use robes in the school's colours. The Code calls for the outside shell of the hood ("see", below) to remain black in that case, however. In general, doctoral gowns are similar to the gowns worn by bachelor's graduates, with the addition of three velvet bands on the sleeves and velvet facing running down the front of the gown. The Code calls for the gown trim to be either black or the colour designated for the field of study in which the doctorate was earned (see "Inter-Collegiate colors"). However, in the case of the degree of Doctor of Philosophy (PhD), although it is awarded for study in any number of fields, the dark blue velvet of philosophy is always used regardless of the particular field studied. For example, if not choosing black trim, a PhD in theology would wear velvet gown trim in dark blue, while a Doctor of Theology (Th.D.) would wear scarlet trim, if not choosing black. The robes have full sleeves, instead of the bell sleeves of the bachelor's gown. Some gowns expose a necktie or cravat when closed, while others take an almost cape-like form. It is designed to be worn open or closed in the front.