[defanor]

> To a Russian speaker, синий and голубой are not shades of each other, they are different basic colors, like blue and green in English.

As a native Russian speaker, I always understood "голубой" as a light shade of "синий" (blue), and that's how it's defined in dictionaries [1,2].

[1] https://academic.ru/searchall.php?SWord=%D0%B3%D0%BE%D0%BB%D...

[2] https://ru.wiktionary.org/wiki/%D0%B3%D0%BE%D0%BB%D1%83%D0%B...

[jpindar]

Like pink and red? Technically pink is light red, but no one calls it that.

[defanor]

I think pink is less clearly a shade of red (it can go a bit into blue), while "голубой" is simply light or pale blue: AFAICT it's used as an alias, and one may call it "light blue" as well.