Abortion is an issue that evokes passion on both sides, and journalists have to be deft in covering it lest their in-boxes overflow with angry e-mails.

So it was this week with the anniversary of the Roe v. Wade Supreme Court decision that legalized abortion in 1973 and the accompanying March for Life that has taken place here every January since.

The demonstration was a big event, as it always is. As the Associated Press pointed out in one of its stories that ran on The Post’s Web site on Jan. 23, it is “consistently one of the largest protests of the year in Washington.”

Staff writer Katherine Driessen wrote the main article on the march, which appeared online and on the front page of the Metro section. She noted that Catholic organizers filled Verizon Center and the D.C. Armory with young people attending morning Masses. That amounted to at least 17,000 people, but there weren’t just Catholics at the protest.

One observer e-mailed that he stood at the Supreme Court and it took marchers two hours to walk by. That’s a big crowd.

But no one knows how big it was. Law enforcement agencies no longer estimate crowd size, nor does The Post. One side or the other will accuse you of being biased if they perceive the estimates as too large or too small.

Still, you can find images of the large crowd taken by amateurs on Flickr or Facebook, and I imagine the AP took some, too. Probably Post photographers did as well.

But these shots didn’t find their way into the main Web photo gallery on the march. And I think this is where The Post fell down in its coverage of the march this year. And that’s mostly what antiabortion readers wrote to me about.

The online photo gallery contains 10 photos: seven tight shots of antiabortion demonstrators, two of protesters from the small abortion-rights counter-demonstration on the steps of the Supreme Court and one that showed both sides confronting each other there. In fact, eight of the 10 shots were taken at the high court.

Emotional shots make better photos, yes, but I would have chosen more from the broad expanse of the rally, and at least one photo showing a lot of cheerful, festive people, which is what I see at most demonstrations that I have covered over the years, regardless of the issue at hand.

Vernon Loeb, Post Local editor, said, “In retrospect I wish we had given readers a better sense of the overall magnitude of the march. . .it was far larger than 17,000.”

Said Post Director of Photography Michel du Cille, “We can never please this crowd. We try for fairness to show both sides.”

Some readers complained that Driessen’s article concentrated too much on teenage marchers and their beliefs arising from seeing graphic photos of fetuses, as if they were being brainwashed. That’s unfair. Driessen and her editors decided on this angle for the story because part of this year’s event was a major youth rally, and Catholic churches have been recruiting young people to the antiabortion cause. The crowd indeed was young. I think that’s a legitimate angle on a story.

Driessen handled her quotes from the teens straightforwardly. I wish, however, she had not used the term “antiabortion ideology” to describe their position. Better to say antiabortion beliefs, position or stance. The word “ideology” has, unfortunately, become freighted with negative baggage.

The Post had lots of other coverage online this week of the abortion issue, much of it very informative. News blogs updated the march story throughout the day online ; Dr. Gridlock previewed and kept up with traffic closures, and AP stories online quoted politicians speaking at the rally.

On Faith, The Post’s blog on religion, had a pro-life writer and a pro-choice writer commenting on the moral basis for their positions, and best of all, one of the Post’s Wonkblog team, Sarah Kliff, did a package on policy that told what had happened in state legislatures on abortion restrictions in 2011 and what was coming up for 2012.

State capitols are where the abortion debate is centered now, and Kliff, through an article, a package of online charts, and interviews with Charmaine Yoest, president of Americans United for Life, and Nancy Keenan, president of NARAL Pro-Choice America, provided a one-stop shop for the state of abortion policy in the United States. And one part of Kliff’s package was illustrated with a photo from the march showing how large the turnout was.

It was evenhanded, unbiased and informative — exactly what Post coverage of this difficult issue should be.

Patrick B. Pexton can be reached at 202-334-7582 or at ombudsman@washpost.com. For updates, read the omblog at www.washingtonpost.com/blogs/omblog.