

In an interview with Toyotarō, Akira Toriyama reveals that he was thinking about having the form be white, but then it would have color-clashed with the “next enemy”, so he figured he should save it for another occasion. On that note, it was constructed by the Capsule Corporation development branch under Bulma’s instructions. And in regards to Vegeta, he adds that he gave Vegeta black clothes because he figured that maybe Bulma had modified his combat uniform to add some slight improvements. In relation to Goku, Toriyama says on Goku he made his hair blue to express how “by overcoming a certain limit he has become both strong and tranquil, able to keep his composure in a fight”. Goku moments after transforming into Super Saiyan Blue

As the author explained it, and as Goku similarly mentions in the movie, the form is as the name suggests the result of a Saiyan with the power of Super Saiyan God further transforming into a Super Saiyan. For the film Dragon Ball Z: Resurrection ‘F’, Akira Toriyama further expanded on the concept of the “Super Saiyan God” transformation featured in Dragon Ball Z: Battle of Gods by combining its power into that of a Super Saiyan.
