They say a picture is worth a thousand words, but student artist Gideon Summerfield might consider that estimate modest. Over 10 weeks last summer, Summerfield set himself the challenge of befriending members of Jewish Care's Holocaust Survivors Centre in Hendon and then getting their consent to sketch their portraits. But what started as a means of keeping artistically busy before going off to study illustration at Cardiff University turned into a commitment to preserve the legacy of his subjects. They include a woman wearing the ring given to her by her wartime lover before he was killed by Nazi soldiers; a man displaying the concentration camp tattoo that was etched across his arm more than 70 years ago; and a loving couple, 62 years married, who met after the war.

"I'd always heard bits and pieces about Holocaust survivors, but nothing in great detail," explains Summerfield, 19, who studied at JFS and Hampstead Fine Arts College.

"But as I sat drawing them, many began to open up about their experiences and we formed really strong friendships. It became less about the pictures and more about my time in their company."

Word of his project spread quickly around the survivors centre, which supports 550 people. Eventually, he completed 10 portraits, all in biro and each the result of a week in the company of the subject.

"It felt very natural to talk to them. They would hear about my life, I would hear about theirs. But then it would hit me. They had been my age when they were separated from their families and thrown into camps. I thought I'd be able to handle it, but it hit me harder than I could have ever imagined."

And although many of those he encountered were used to sharing their experiences, speaking at schools and to other groups, some had buried painful memories so deep that even their families knew little of what they had been through.

Surprisingly for both parties, Summerfield's sketchpad was the springboard for such survivors to finally speak out. "There was this one lady who never wanted to say anything," he recalls. "But during one session, she started to talk and became very emotional. We were both as shocked as each other. She's now working with counsellors at the centre to open up about her past."

A striking feature of Summerfield's portraits is their intimacy, a quality he feels was achieved by asking the subjects to hold something they cherished. These varied from photos of loved ones to jewellery and each memento was highlighted in colour to emphasise its passage through time. For 87-year-old Auschwitz survivor Avram Schaufeld, the cherished thing he wanted in his picture was his wife, Vera.

Survivors centre manager Aviva Trup says that "having Gideon here was like having a catalyst for creating legacies. He became that bridge people would cross to tell their stories and his art became their 'trust tool'. We're now using the pictures in the training of our carers, because they are such a striking way of relating someone's story.

"Once you've heard a person's history, your care for them will change immediately. You'll be far more considerate about not slamming doors, which could bring back memories of Kristallnacht, or not giving them thin soup, as it may remind them of eating in the camps."

Summerfield says his ability to connect through art has always been his means of self-expression. "With most things, I find it difficult to form opinions. But if I look at a person, I'm constantly thinking about how I would draw and connect with them."

As an example, after completing his GCSEs at JFS, the Finchley resident realised he only knew a small fraction of his 300-student year group. So he set about drawing them all. "It was a fun way to get to know people," he says.

For the survivors centre project, he attributes the strength of the portraits to the subjects. In the case of the Schaufelds, he "fell in love with the chemistry between them". And the admiration is mutual. "He's a very nice boy," says Vera Schaufeld, who has lived in the same Wembley House for half-a-century with her husband of 62 years. "We felt he showed a genuine interest in us, which we thought unusual for someone so young."

The 84-year-old had arrived in the UK, aged nine, on the Kindertransport. Her husband-to-be endured a rockier road to survival. Born in Poland, he was sent to Auschwitz aged 16, leaving when the camp was liberated. Although he believes it is "essential to tell people the stories of the Holocaust", it is something he himself has struggled with down the years.

"I never even spoke about it to my children, but it came out in different ways," he says. "If my daughter left her food on the plate, I would have to finish it - I couldn't bear to leave it."

The legacy of Summerfield's project was cemented in January when the Holocaust Memorial Day Trust exhibited his portraits in Westminster. And he this week presented the originals to the survivors, so that they could pass them on to their families.

And he'll still be seeing them at the centre's Tuesday art class.