Left/right and right/left petals?

[tropterrarium]

Which petal on an orchid flower is the left, which one the right?
If you look at it face on left is left, right is right?
Or in growing direction, so when you look at it, left is right, and right is left?
It is the same question as with the human heart, it is on the left side from the perspective of the person, but on "right" from the perspective of an external viewer facing the subject.

I sort of suspect it is in viewing direction, and in natural orientation, i.e., with lip down (in most cases, though there are exceptions, of course). Otherwise we add the further complication of resupination. That fits with the notation of "dorsal sepal" opposite the lip, which starts pre-resupination in ventral position.

This is not about correct vs. incorrect terminology, but rather what the generally accepted standard is. Any references would be greatly appreciated.

Thanks for your wisdom!