Fair point, but I’d argue with most of Mondrian works and some other artists, the composition is equally strong regardless of orientation (or at least in multiple orientations.)
I am not sure how Mondrian worked, if he rotated canvas to better access specific areas, whether the “up” and “down” was predetermined. But I do know artists like Pollack didn’t have a set orientation while working on his works. He worked around the whole piece. Certainly the dimensions usually dictated a landscape format vs portrait, but IIRC my modern art history classes, he would sometimes decide on proper orientation after the fact.
You’re right an artist usually has a specific orientation in mind either before, during, or after the piece is completed. I am not suggesting Pollack or Mondrian didn’t usually have a “proper” orientation in mind. But it isn’t always clear if they did, and I don’t think the artwork suffers from a different orientation in some cases. I used to look at a lot of abstract expressionism and I would often turn the books around to see how orientation changed the composition. I was trying to “get” what makes good composition. And in some works you can definitely find a clear "winner’. But other times I felt more than one option were equally strong.
The gallery got off easy. Eva Gabor (the nice one) had to flee New York because of angry art critics when it was realized her painting was upside down too.
That reminds me.
I did this test with some friends years ago when my nephew was a little boy.
Below are 3 paintings. Two were done by him when he was 4, one of them is hanging in the De Young Museum in San Francisco. I took the pictures the same day when they used to live in the Sunset.
Who can guess right. Hide/blur your answers. And if you’ve been to the De Young and seen the one that hangs there, don’t answer.
[ETA: oh, I misread your post-- I was commenting on the orientation of those pieces, but you want us to guess which one wasn’t done by your nephew. My guess is: the bottom one is in the De Young.]
I mean, that’s not necessarily a stretch. I don’t know how he worked, but I know several artists who turn their work upside down periodically to get a new perspective on it while they’re working on it. I know one who actually throws the canvas on the floor, so it lands randomly, and then makes that the new “up” and “down.”