Passementerie Buttons
Like the 11th Doctor’s velvet waistcoat, his “scales” waistcoat(s) had two different sets of buttons over the course of its on-screen appearances.
Generally speaking, for its early appearances, the waistcoat had passementerie buttons.
Aside from their unique, braided construction, perhaps the most unique, confusing, and surprising element of these passementerie buttons is their color.
Post-production color shenanigans notwithstanding, they sometimes simply registered on-camera as gray.
Other times, they only appeared to be a subtly different color.
Sometimes, they appeared to take on a metallic gold, silver, and/or bronze color – especially under flash and/or bright lighting.

Up close, while they could photograph as more of a “khaki” color, in actuality the buttons are light brown.
Tip: Focus on the darker areas toward the outside of the buttons, and inside the crevices of the braid.
Two final notes about these passementerie buttons:
First, they appear to have been ⅝” (15mm) in diameter, also known as 24L, but this is their total diameter, not just of the base onto which the button is constructed.
Second, this was the same style passementerie button used on Eleven’s velvet waistcoat, as well – but of course in black.
Horn Buttons
The other buttons used on the “scales” waistcoat appeared to be standard, ½” (or possibly ⅝”), 4-hole horn buttons.
The first proper appearance of the 4-hole buttons was – paradoxically – also the first “proper” appearance of the waistcoat itself. His waistcoat had them throughout the entirety of “The Rings of Akhaten.”
Interestingly, some publicity photos for “The Rings of Akhaten” showed the Doctor wearing the waistcoat with passementerie buttons!
(Of course, they do appear to be the same photo, with Matt Smith inserted onto a separate background. Even the photo with the white background appears to have been part of a single photo shoot, possibly intended to yield promotional photos for several different episodes.)
In other publicity photos for the episode, though, his waistcoat had the “proper” 4-hole/horn buttons.
In any event, the 4-hole/horn buttons wouldn’t be seen again until “Journey to the Center of the TARDIS,” when his waistcoat would again have them throughout the entirety of the episode.
These buttons were also on the waistcoat during its (brief) final appearance near the beginning of “The Time of the Doctor.”
It’s difficult to get a reliable color reading on the buttons; I think they’re probably dark gray, but without additional (and higher quality) references, all I can determine with any degree of certainty is that they’re notably darker than the “scales” fabric itself.
Button Spacing
For both button styles, the waistcoat had five buttons.
Although the vertical spacing appears to have been even, the horizontal spacing of the top and bottom buttons may have varied a bit.
Sometimes the upper and lower buttons appeared to be horizontally in line with the others.
Other times, the top and bottom buttons were clearly positioned slightly away from center, not in line with the middle three buttons.
As best I can tell, the buttons appear to have been spaced approximately 2″ apart (common practice, according to the similar theatrical and historical/Victorian-era waistcoat pattern blocks I researched), although I did occasionally read a 1 ¾” button spacing.
Wearing Styles
About half the time, the Doctor wore his waistcoat completely buttoned – that is, with all the buttons done.
He wore his waistcoat fully buttoned throughout the entirety of “The Rings of Akhaten” and “Journey to the Center of the TARDIS.”
He also wore his waistcoat fully buttoned for the corresponding publicity photos.
He again wore his waistcoat fully buttoned near the beginning of “The Time of the Doctor.”
However, in a manner perhaps reminiscent of that of his immediate predecessor, he sometimes wore his waistcoat partially unbuttoned!
He wore his “scales” waistcoat with the bottom button undone throughout the entirety of the episodes “Cold War” and “Hide.”
He wore his waistcoat with the bottom button undone for the corresponding publicity (and behind-the-scenes) photos of “Hide.”
However, in the publicity photos for “Cold War,” he wore the waistcoat both ways.
In some photos, he wore it fully buttoned.
But in this photo, he wore it with the bottom button undone (as he did in the episode).
When the lowermost button was unbuttoned, it was quite obvious that it was horizontally positioned slightly farther from the center than the middle buttons were.
Buttonholes
The buttonholes were made using purple thread.
And finally, the buttons were attached to the right side of the waistcoat, with the buttonholes on the left – as is traditional for men’s garments.
However, there was also this flipped shot from “Hide,” in which both the waistcoat buttons and Matt Smith’s hair were clearly the opposite of normal – then again, timey wimey stuff was happening, so who knows?