Problems with colour pairing

Two-colour brioche: why is it so bloody hard to pick two colours that work together ?

It seems so easy when you start off with your great pattern and your two colours of whatever yarn you’ve chosen … They look so good together in your knitting basket – can’t fail to be terrific.

But they do.

The reverse side is just – wrong.

Why on the front does the green vertical row sit proud and the violet row provide merely background; and on the reverse the green is competing with the foreground violet ?

Or why does the front look just as you hoped but the reverse looks simply muddy ?

Here the front gold stands out as vertical rib; but it also stands out on the reverse, in almost the same way !

Beautiful. But only the front. On the reverse the pattern is close – crowded, even. This effect is commonly seen, where the back of the pattern appears to be somehow more tightly knitted !

Rather puzzingly, that effect is not seen here: this is good ! I attribute the difference between this screen-grab and the previous one to the fact that this one’s colours could scarcely be more opposed; whereas the one above uses two shades of the same colour.

I am now on a mission to find some kind of equation that will result in a pairing of any two colours that will work perfectly together to result in brioche that doesn’t fight against what it’s meant to look like.

As I understand it, that is. As far as I have learned, two-colour brioche knitting should be reversible but for the colours being swapped.

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(None of these is mine: I screen-grabbed them all from the Web in my wish to at least partly indicate what is so frustrating me.)