Doctor Who: The Complete David Tennant Collection is presented on Blu-ray courtesy of BBC with AVC encoded 1080p transfers in 1.78:1. Tennant's tenure in the role is notable for a reason in addition to it's length - it occurred during the switchover from standard definition to high definition, at least if you include the so-called "Specials", which were in essence a limited run set of new episodes, and which are part of this expansive set. Therefore, fans need to expect something akin to a two different Doctors, with Series 2, 3 and 4 obvious upscales, and at least most of the specials looking considerably better, having been culled from native high definition sources. (I haven't been able to find any really verifiable information about this, but to my eyes the first special, "The Next Doctor", looks like an upscale to me as well, something bolstered by the fact that the Confidential about that special is in 480i on the Supplements list I've included below, while the rest of the special Confidential episodes are all in 1080i.) There are persistent upscaling "bugaboos" throughout the presentation of these upscales, including noticeable stairstepping and signs of digital sharpening (with some resultant haloing), but detail levels can often be surprisingly strong, at least given an understanding of context. The palette also looks decently fresh and vivid. Things improve markedly with regard to most of the specials, and some of the other supplemental material, like the animated specials and the two part "The Wedding of Sarah Jane Smith", from The Sarah Jane Adventures, a perhaps understandably lesser remembered Doctor Who spinoff (see screenshots 21 through 25 for a look at the animated fare as well as the Sarah Jane episodes). In the native high definition material, fine detail levels enjoy a rather considerable uptick, and the palette looks nicely suffused and vivid. Even in the native HD presentations, CGI can at least occasionally look a little soft. My score is a kind of "average" spread across the entire content of this expansive set: Series 2, 3, and 4 probably hover in the 2.5 - 3.5 range in terms of video quality, while the native HD material is at least at 4.0 levels and I'd argue up toward 4.5 levels quite a bit of the time.