My research chronicled this through Dragon Ball’s first three-and-a-bit years, by using the Dragpn Ball: A Visual History art book.
Famously, the Dragon Ball anime that began in 1987 sorted the colours out by using blue for Goku’s “Mount Paozu” gi with the bow belt, and using red and black from the manga’s limited colour pages for the Turtle School gi, as these were initially far more common than the “key art”.
In the lists below, “Issue” refers to the issue of Shonen Jump that the artwork appeared in, often also referring to the manga chapter’s title page from the issue as well. If there’s a bunch of entries for a single Issue, it’s most likely for a calendar!




As you can see, by 1987 Toriyama was colouring the Turtle School gi almost enttiely in a shade of orange, with the colour being the primary one in 1986. While the Red gi was still used in the Limited Colour Chapters, it would not be used in “key art” after this point aside from one instance in 1989. Yellow gi would make a comeback in the early 2000s as Toriyama started making more Dragon Ball art digitally.
Most famously, the 1989 Dragon Ball Z rebrand of the anime introduced a small but important change. Because Toriyama had been colouring the Turtle School gi primarily in orange since 1987, they reflected this in Z, also using the blue armbands and undershirt from this colouring too.
The blue gi meanwhile would not appear again in Toriyama's artwork for another nine years. Starting in January 1996, the blue gi would exclusively appear on Kid Goku to refer to his pre-Turtle School days, much as the anime had done in 1986. A dark green would also be used, and both of these colours also tend to be used for “End of Z” Goku.
The 2013 Color Editions meanwhile would apply the orange colour to Goku’s starting “Mount Paozu” gi, which is incorrect for 2013 because by that point Toriyama had been using blue for this outfit for seven years. However it’s also somewhat understandable: of all of Toriyama’s fully-coloured ink pages from the manga’s original publication, Goku only wears blue in Chapter 1, before switching to orange for the rest of the manga’s run.

