AnImprimatur, (PROSE:The Two Doctors,Interference - Book One, et al.) also called anImprimiture orbio-imprimatur, (PROSE:The Book of the War) was a type ofGallifreyan technology used byTime Lords to design or modifybiodata.

TheRassilon Imprimatur was a code designed byRassilon and added to Time Lord biodata. (TV:The Two Doctors, et al.) This bio-imprimatur protected its recipients fromdeep time phenomena (PROSE:The Book of the War) and allowed them to put themselves in different time states by focusing on equations. (PROSEl:Interference - Book One) This enabled Time Lords to travel in theTime Vortex (TV:The Two Doctors,PROSE:Divided Loyalties) andtransmigrate. (PROSE:Interference - Book One)

TheCatherion Imprimiture was an experiment, potentially initiated bythe Imperator, that involved modifyingcasts into new weapons calledbabels. Its name derived from the extinctHouse Catherion, whosechapterhouse was used to house the project. After fifty years, the experiment was ended whenone babel escaped and massacred the inhabitants of the house. (PROSE:The Book of the War)

TheImperiatrix Imprimatur was a biodata imprint ofImperiatrixPandora that infectedRomana and, later,Braxiatel, who each resisted its influence with limited effectiveness. (AUDIO:Lies,The Curse of Fenman, et al.) Pandora eventually used the Imprimatur to build herself a new body. (AUDIO:Imperiatrix)

WhenPresident Romana scrambled theImprimatur Cortex in the berthing bays at the start of theGallifreyan Civil War, allTARDISes were grounded. (AUDIO:Fractures)