A font object in PDF is a description of a digital typeface. It may either describe the characteristics of a typeface, or it may include an embedded "font file". The latter case is called an "embedded font" while the former is called an "unembedded font". The font files that may be embedded are based on widely used standard digital font formats: Type 1 (and its compressed variant CFF), TrueType, and (beginning with PDF 1.6) OpenType. Additionally PDF supports the Type 3 variant in which the components of the font are described by PDF graphic operators.