I went back to the article, which does say more or less what I wrote: What astronomers hope to finally see when they add up all the signals is a halo o

I went back to the article, which does say more or less what I wrote: What astronomers hope to finally see when they add up all the signals is a halo of light surrounding a dark circle -- the shadow of the black hole. The crescent of light comes from luminous gases, heated to hundreds of billions of degrees, that orbit just outside the black hole, tracing the region just beyond the event horizon. So when the grandparent said, "a completely black rectangle", that's probably not true. Which is was what I was responding to. Please feel to correct us non-experts (but it's not terribly useful to shut down discussion without explanation other than "I am a physicist").