Recently, I’ve come to realize how modern technology leads us to a deeper understanding of our past.

I’m not talking about new scientific methods and equipment that enable a more extensive look at historical sites, like the recent report that infrared scans have pointed to the possibility of a previously unknown chamber in King Tut’s tomb. I mean something on a much more personal level.

Many people belong to Internet groups dedicated to looking at our past, a number of them focusing on New Orleans and Louisiana history. Regardless of their educational level or their grounding in historical studies, members find these groups accessible, probably because of the old photographs there.

You’ve heard the bromides: “Every picture tells a story”; “A picture is worth a thousand words.” But they’re true, and these old photos are better than dry recitations of historical facts.

In one group devoted to the recollections of African-American life in New Orleans, someone posted a picture of what were called “screens.” These were little placards that delineated where the seating for white bus riders ended and where that for the “colored” ones began.

The screens had two pegs on the bottom, and the bus and streetcar seats had corresponding holes in the seatbacks. The placards could be moved back and forth as needed.

Many who lived in those times disclosed quiet acts of disobedience. High school students would toss the screens out the windows — usually open since the buses weren’t air-conditioned — when the drivers, all white at the time, couldn’t see them doing so.

Others talked about moving the screens to the front of an almost empty bus to give the “colored” section the lion’s share of the seating, at least for a time.

Small victories.

One person, who according to his profile was both young and black, asked why African-Americans didn’t just start their own bus company rather than patronize one that disrespected them. A good question, but it reflects a surprising lack of knowledge of the times.

Bus companies are regulated, like utilities. In fact, the transit company at the time was part of New Orleans Public Service Inc., the electricity and gas supplier for the city.

Starting a competing company would have required government approval (as well as a lot of money). You can assume that would not be easily forthcoming from an all-white government in an area where it was difficult for a black person to even register to vote.

Another discussion had to do with the noontime sirens that went off in the city back in the 1950s and ’60s. Much like the air-raid sirens of World War II, they were set up to warn of impending attacks.

Each weekday at noon the sirens would sound, presumably a test to make sure they were in working condition.

It was a high-anxiety period, with the United States and the Soviet Union careening from one crisis to the next — Hungary, Berlin, Cuba — any one of which might set off a world-destroying nuclear war.

If you were oblivious to the time of day, as most kids are, the sound of the siren would send you scurrying to find a clock to make sure it was noon, because if it wasn’t, then real trouble was in store.

The cleverer kids among us concluded that if the Russkies were really smart, they would bomb us at midday, when most people would ignore the warning sirens.

Fortunately, they never did.

Incidents like those from the past are what made us the people we are today, and we learn more about those times thanks to the technology of the present.

Dennis Persica’s email address is dpersica@theadvocate.com.