AMNA NAWAZ: A new book of photography offers a unique lens on the impact of war on fighters and civilians alike.

The author, Corinne Dufka, formerly led the West Africa Division at Human Rights Watch, where she spent more than two decades documenting human rights abuses through victims testimonies.

But, before that, in the 1980s and 1990s, Dufka was a war photographer covering some of the world's most brutal conflicts.

Many of her photos are now being published for the first time in her new book "This is War."

I sat down with recently for our arts and culture series, Canvas.

Corinne Dufka, welcome to the "NewsHour."

Thanks for being here.

CORINNE DUFKA, Author, "This is War: A Decade of Conflict": Thank you very much.

It's a pleasure.

AMNA NAWAZ: Some of these photos are more than 20 years old now.

What made you want to go back into your archives and your negatives and look through these again?

And what was that process like?

CORINNE DUFKA: Well, it was a very dynamic process.

And like any book project, it's multilayered.

I wanted to do this book first as a personal journey to try to come to terms with and understand what I had seen decades ago, phenomenal brutality through the lens now of being a mother, through having studied policy.

Also, I wanted to add to the historical record of the conflicts covered, many of which were and continue to be quite undercovered, and to the role that women played in war photography.

But, more importantly, I wanted this book to spur conversation on the notion of conflict recidivism or relapse, because, in the process of editing, some of the pictures that I took 25 years ago could have been taken today, because those countries had relapsed into war.

AMNA NAWAZ: We're going to talk about some of these photos specifically.

I just want to do a quick warning for our viewers.

Some of these photos are quite graphic, and they may find them disturbing.

But each chapter basically covers one of the conflicts that you cover.

There's a real intimacy to them too.

Take me back to El Salvador.

There is a man there that you have met named Herbert Anaya.

He ran their human rights commission, I understand.

You were a social worker at the time.

He asked you to set up a photo documentation program.

And when he is tragically murdered, you are there to take this photo that ends up running in The New York Times.

What do you remember about this picture?

CORINNE DUFKA: Well, I remember getting a call early in the morning saying that he had been gunned down.

And this was in a very difficult moment in El Salvador's history.

I rushed out -- it must have been, I think, 7:00 or 8:00 in the morning -- and found Herbert lying on the ground in a pool of blood.

I took the picture.

And this is a person with whom I had come to know and respect and played a vital role in El Salvador in uncovering what were some really horrific human rights abuses.

AMNA NAWAZ: Does it change how you work when you know the person on the other side of the lens?

CORINNE DUFKA: Yes.

The pictures are very intimate.

It's very clear from the very beginning of this book as one starts to look at it that the vast majority of those pictured, the images that I have are of civilians, because, in the majority of conflicts that I covered, the armies, the militias had basically wage war against the civilian population.

They weren't fought in battlefields, rather, in the villages.

So I get very up close.

I'm grateful for civilians, for the combatants who opened up their houses and hospitals and battlefields and let me in so close to be able to communicate to the world what it was that they were experiencing.

AMNA NAWAZ: You write about a group of teenage fighters that you were following in Liberia and these photos that you took in the moment as they attacked an armed man in front of you, and they stripped him and they killed him.

And you wrote later that you felt sick as you were developing the negatives.

And you wrote in your book -- quote -- "I agonized over whether I could have prevented this random, unexpected killing."

How do you balance in the moment the mission to remain an observer -- that is your job - - but also the human impulse to help?

CORINNE DUFKA: Yes, it's interesting, because I didn't think that they were going to kill this man.

That's part of human nature, is to somehow deny that the worst could happen.

This group of fighters who I was tracking with my camera that morning came upon this man who was simply foraging for food.

So they just picked this man up because he happened to be from another ethnic group, dragged him through the streets, and then, within a moment, they stripped him and shot him.

And it was horrific knowing -- and this has happened a number of times in my career -- that you're photographing someone, you know that they have perished before their family does.

So, it was a horrific scene that was unfortunately repeated again and again in Liberia and in so many of the conflicts that I have covered.

AMNA NAWAZ: There's this line you write in the book that stuck with me.

You say: "What the eye sees, the brain records."

To bear witness to all of this in the many ways you did, and very young at the time, what kind of toll does that take?

CORINNE DUFKA: Well, it certainly leads to dehumanization, covering mass atrocities.

I went from El Salvador to Bosnia and then to -- my first conflict in Africa was the Rwandan genocide.

And one has to get a job done, because it is a journalist's responsibility to communicate to the outside world the horrific things that we're seeing.

But I think also one gets numb.

And that happened to me.

That's ultimately what led to my decision to leave the profession, is because I didn't recognize myself anymore.

AMNA NAWAZ: So many of these images are reminiscent of things we see today, as you mentioned, conflicts that rage on around the world.

What would you say to people about why it's both necessary to bear witness, to look at these kinds of photographs, to know what's happening on the ground, but how they can keep themselves from becoming numb to it all?

CORINNE DUFKA: Yes, it is a balance.

I mean, to a certain extent, not showing these images -- and I think, over time, what with the emergence of citizen journalism, when people just post whatever they want without it being edited for sensitivity, for content and so on, has in some ways intensified dehumanization.

But it's so important to stop the moment, especially with us being inundated with photographs, to stop the clock, to stop the chatter, to really reflect on the impact of war and the reasons for it.

AMNA NAWAZ: The photographs are so potent and so necessary.

So, thank you for bearing witness, so the rest of the world can too.

The book is "This Is War."

The author is Corinne Dufka.

Thank you.

CORINNE DUFKA: Thank you.