The paintings in the article are mostly 15th century, which is only early renaissance. The understanding of light in painting was still somewhat limited in those times. I think in the case of almost all of these paintings it's more a matter of technical competence rather than artistic intention (exceptions include "Madonna and Child Enthroned with Saints" where I reckon the shadow ends early for compositional reasons). It's interesting to look at this to get a sense of the various ways people can get something wrong before someone gets it right.

It can't be that hard to sketch what you see on a sunny day or in candlelight and start to make sense of the rules, right? Getting perspective to look right in paintings seems like it should be a more challenging invention than how shadows behave around corners, walls, and other objects. Getting the sizes and shapes of the shadows correct would be another matter, however.

So I am willing to assume that if a shadow fails to climb up a wall, it's because the artist thought it looked better without the shadow on the wall.

I'm of course no art historian of any sort, don't even play one online. However, yes, perspective, proportionality and light were being paid more attention to in art at that juncture in art. Often, in current and historical naive and current and historical primitive art, we see the same issues with bad perspectives and bad shadow treatment. That said, in many cases the artists knew but did not care and had a different focus. Still I agree that in many cases the artists didn't want this "interference". Just as today your roadside artists may not include all the municipal electric wires or all the trash or cloud shadows and so on in one of their paintings when capturing an atmosphere or panorama.

In "Polittico di Sant’Antonio" the cut-off shadow is at the edge of the painting, so I imagine that one might have just been an oversight from the painter. But in general, it is pretty difficult to get shadows right when you're not painting from life since you don't just need to understand how the basic rules work, you also need to be able to imagine how it works and apply it.

But more generally, being among the first to figure things out isn't easy. Nowadays you can look at photographs and paintings like the works of 19th century academic painters and say "this is how realistic paintings are supposed to look", but back in the 15th century all you would be able to see is other people doing it not quite right. I feel like it takes a bit of genius to be the first to do something right, and frankly the average artist isn't that smart.

Linear perspective was "invented" in 1415 and codified in a 1450 book, at which point the concept started to spread but still wasn't widely understood. A lot of the paintings in this article have extremely wonky perspective as well. This was a transitional era in art history when formal rules for realistic painting were being developed but weren't necessarily widely or correctly used.

> The understanding of light in painting was still somewhat limited in those times.

I'm confident even cavemen saw and comprehended shadows against a wall.

Btw, do any of the "humans" in these paintings pass the "not the real thing!" test? It is a painting and in every instance it is clear the correct shadow would mess up the composition.

Next stop an article on "How poets have gotten grammar wrong all these years".

As an amateur artist myself, I've often fudged shadows and shading to emphasize or de-emphasize certain things. Often I'll make slight "token shadows" to at least have enough to say "here it is" if somebody fastidious complains, but I'm still happy to downplay a shadow if it fits the intended narrative of the work.

Those actually judging the art of the times probably didn't really know or care, as the illustrations were often done for social reasons at least as much as decorations. As the canon of "shadow science" increased, there would be more pressure to also please professionals who may judge your work and pass on the word. "Don't hire Bob, hire me, for he does shadows wrong. Here, I'll show you using candle light and these books...".

Pleasing customers and pleasing artists are often different things. Bach pleased artists much more than "customers" and thus made a middle-of-the-road salary despite being a musical genius. Mozart was arguably the same way, as he had some trouble keeping up with short-term fads.