Well this is a new one. What does it mean? It was sent to me in an email and it’s interetsing because what the person seemed to mean by it is not exactly clear from the explanation Ciberdúvidas gives. First, here’s Ciberdúvidas
‘Numa distribuição circular das cores verificamos que o amarelo se opõe ao azul assim como o vermelho se opõe ao verde. Por esse facto, o contraste entre o azul e o amarelo bem como o contraste entre o vermelho e o verde são os mais bem definidos.
in Ciberdúvidas da Língua Portuguesa, https://ciberduvidas.iscte-iul.pt/consultorio/perguntas/ouro-sobre-azul/13660 [consultado em 29-11-2023]
Como o ouro brilha, o contraste é ainda mais impressionante. Esta combinação era muito frequente no vestuário das rainhas e até dos reis desde o Renascimento aos finais do século XVIII.’
So, basically, the first two sentences explain that Gold and Blue are opposite each other in a colour wheel so they are a strong contrast and they stand out well. So… it means it’s a contradiction then? the exact opposite? That didn’t seem to be what my email correspondent meant. But the second part of the text gives more of a clue: the fact that the yellow pops out so well makes it a popular combination in royal clothing (remember the Queen’s controversial hat a few years ago?). So that might mean it’s something different but in a good way.
And sure enough, if you look up the phrase on reverso-context, it gives most of the translations as something like “the icing on the cake”: something that would be a nice, striking addition to an already good thing, which I think is how it seemed to be being used. I think this is a rare example of Ciberdúvidas not being very helpful, but maybe that’s because they assume the person asking the question already knows the definition so it didn’t need spelling out. Fair enough!
Luso 
The question that the person had asked in Ciberdúvidas was “‘Gostaria de conhecer a origem da expressão «ouro sobre azul».”, so effectively they asked the origin of the expression, not the meaning — and the answer that Ciberdúvidas gave was adequate and helpful in this context.
LikeLike
Yes, true. I think i said maybe they assumed they knew, but probably should have said “clearly the person already knows”. Sloppy phrasing on my part. Thanks for pointing it out.
LikeLike
Para saber mais sobre esta e outras expressões que fazem referência às cores posso sugerir que oiçam (ou leiam) o podcast 125 de Expressões Portuguesas “cor de burro quando foge” https://sayitinportuguese.pt/podcast-siip/125-cor-de-burro-2/
LikeLike
Ao que parece, recebo mais comentários quando faço erros. Vou aprender desta dica de marketing.
LikeLike
There is another interpretation for this sentence related to decorative styles.
Gold over blue was a caracteristic of the decorations in the Barroque and late barroque (Rococo Joanino in Portugal, late 18th C.) styles. It pertains to finish the decoration of a surface with the best possible color combination for a backdrop to enhance and highlight what is shown in front of it, like an image or a statue or a reliquary. It also applies to the combination of the Portuguese decorations of blue and white color tiles with gold leaf covered wood frames surrounding paitings covering big wall surfaces that can be seen in churches and palaces.
LikeLike
Thanks for adding the extra detail, João!
LikeLike