Thomas Borberg: It's not about positive stories or negative stories, more that you have to be able to feel it in your stomach. I think it's the strong stories – and often the negative stories – that make the greatest impression on us. That's how it is and how it should be. The final result of the judgment should reward the best stories told in the best way.

Emma-Lily Pendleton: Do you think many wildlife photographers are submitting images to the WPPh Contest?

Helen Gilks: I'm not sure how aware of it they are. I think for stories, yes, because a lot of the National Geographic stories enter and are successful. But in single images, wildlife photographers don't think it's the competition for them. Let's hope that changes.?

Emma-Lily Pendleton: Do people tend to enter photographs that are similar to previous years' successful images?

Helen Gilks: There is a lot of copying of styles that are successful in competitions. There's a wildlife photographer called Bence Máté who developed a system of ground-level perspective photography from underwater hides, and suddenly we just saw loads of these pictures. But I think most people seriously entering competitions understand that it has to be something fresh and different to what's gone before.

Thomas Borberg: You see a lot of photographers using drones now, but you see a lot of bad pictures, because people don't tell a story, they just show you another point of view.

Similarly, if there's a big story – such as the Rohingya crisis or the refugee crisis in Europe – photographers tend to go to the same places, because newspapers or magazines send them there. But some photographers are so good that they are still able to stand back and see the story from another perspective, and of course that stands out.

Emma-Lily Pendleton: When it comes to judging, what weight do you give to the story versus the aesthetic of the photograph?

Thomas Borberg: It depends on the image that you see, and the discussion within the jury. One of the things that I like about the World Press jury is that, at least this year, we were open minded. You could change your mind during the discussion. You could start by backing an image that had been picked for its photographic quality, but then be more convinced that the story behind another one made that even greater. It's not necessarily a 50/50 split, it depends on the image and the story behind it.

Magdalena Herrera: There are several things that come into consideration – the surprise, the emotion, the composition, and the capture as well. That's the thing with photography – it's made up of so many parameters.

Emma-Lily Pendleton: How important is the ability to edit and string a story together??

Magdalena Herrera: You have to be able to tell your story in a good way. You have to have a start and an end, and something happening.

Thomas Borberg: Way too many people get this wrong, and it's too bad. Sometimes we see stories with three, four or five strong single images, but nothing that actually combines them into a narrative. Sometimes it makes you think, 'Argh, they need help!'?

Helen Gilks: Yes, some photographers don't understand what a story is, that's for sure. I wanted to ask Thomas and Magdalena whether you think the portfolios that have been published, where the photographers have worked quite closely with an editor, have an advantage? Do you see those rewarded more than the photographers who have perhaps not been published and have done their own edit?

Magdalena Herrera: We don't know how many edit their own work. The photographer, like a writer, has to understand that at some point, you need someone from outside to tell you that they understand the story. The industry is changing – before, we had editors at the agencies to do that work for photographers, and we had more editors in magazines and newspapers, but there are fewer editors now.

Emma-Lily Pendleton: So editing is becoming an important part of being a professional photographer?

Magdalena Herrera: Yes, if you want to tell stories.

Thomas Borberg: I do agree that you should seek advice, via an editor or another photographer – not just because of the World Press Contest, but because it will help your work. You should do it before you enter, to make sure, from the beginning, that the story you share is the best possible one, and that it will be understood by the public.

Magdalena Herrera: The narrative and the consistency of the mood throughout the story [are important].

Emma-Lily Pendleton: What is the key component of a winning image??

Thomas Borberg: Emotion. You need to leave people feeling something. It might not be a specific feeling, but you need to leave something so that they will keep on asking questions.

Magdalena Herrera: Not everything that provokes emotion is negative. It can be a 'wow' feeling, too.?

Helen Gilks: Yes, great beauty can create a strong emotion too, can't it??

Thomas Borberg: Mads Nissen's [World Press Photo of the Year-winning] image from 2015 was about love, but it was about forbidden love around the world. Is that a positive story or a negative story? What we saw was people having sex, which is so normal, it was just that it was between two gay men [in Russia, where LGBT people have faced discrimination and harassment].

Magdalena Herrera: There's always a dialogue between different elements – what you see, and what's behind it. In fact, Mads Nissen's photo by itself was nice and quiet, and exuded love, but the context was that love was threatened in a terrible way. Each year, each winning image has that kind of conflict between what you see, what you feel, what it is, and what message it gives.

Thomas Borberg: I think it's important that when the jurors are making the final decision about picture of the year, they pick elements that send a signal about the time that we are living in. John Stanmeyer's 2014 image of the refugees on the beach looking for cell phone signal was about fleeing, about migration – one of the biggest issues around the world. The smartphones showed that it was a modern crisis, because you couldn't have made this image 25 years ago when [few ordinary people carried] cell phones.

Emma-Lily Pendleton: The rules of World Press Photo have become stricter [since 2016] with regards to staging and manipulation, and photo editing. How tough is the verification process?

Magdalena Herrera: Very tough. Every file is checked technically, then all the captions are checked and double checked by an independent fact-checking team. They will sometimes then interview the photographer and check the news [to make sure their story matches up with reported events]. It's pretty serious, but they have to do that today. In the times of fake news, more than ever you have to be tough on [manipulation] to be credible.

Thomas Borberg: I think the World Press Photo Contest is an ambassador for truth and trust, not only on behalf of World Press Photo, but all professional photographers, especially photojournalists. You can't be almost right, or just a little fake – it's either there or it's not. If you try to manipulate the stories, then there's no fundament for photojournalism to stand on. It's not only about cropping an image or adding something. If you are a professional storyteller, you should have captions telling the true story, because it's not only about what we see, it's also about the story behind it.

Magdalena Herrera: And the practice of how you represent people – you have a huge responsibility there.

Magdalena Herrera: I remember judging one year when there was a little snake that was opening its mouth. We found the photo very pretty, but the jurors are scientific, and they said, 'Well this little snake doesn't open its mouth like that, if you don't tickle it first.'

Emma-Lily Pendleton: What would you say to people who are considering entering next year?

Magdalena Herrera: This year, as a chair, I asked all the jury members what they were looking for and 90% of them said new, challenging approaches. Not just in terms of technique, but also in the photographers' point of view about what's happening in the world. In the Environment category, for instance, and Long-Term Projects, you have to step in and bring your perspective to the story. By that, I don't mean staging or anything like that – I mean showing your own reflection on the topic. It's about how you place yourself. What distance, what degree of intimacy. Should the story be told with a sense of humour? This is what I mean by a new approach, or your own approach.

Thomas Borberg: Ask yourself, why did you become a photographer? It's something about curiosity, and being able to open people's hearts and minds, stepping into these intimate places and being able to share that experience. If you go back to that, to the photographic DNA of curiosity, combine it with a small amount of technique, and find clever people to help you edit the stories, then you are halfway towards being a Photo of the Year winner.

To see the full list of contest categories, the rules and judging process, and to enter the World Press Photo Contest, visit World Press Photo's website.