Wolfgang Tillmans is wearing a plain red T–shirt, builder jeans and decidedly unfashionable trainers. He's tall, but unimposing. Sometimes you have to finish his sentences for him because, despite more than 25 years in the UK, the native German's vocabulary can falter.
He walks me around his new solo show at the Tate Modern, "Wolfgang Tillmans: 2017", and the first thing that hits me is how hugely broad in scope his work has become over the past 14 years (the earliest piece in this show was made in 2003). There's portraiture, still life, magazine work, video, abstract photography, audio and collage. Subject-wise, he deals in intimacy, modernity, post-truth politics, globalisation and even the gentrification of London. It's so eclectic it could almost be a group exhibition.
Actually, all that is the second thing that hits me. The first is a huge photograph of a scrotum hanging on the wall. "Sexuality is still really important to me," says Tillmans, smiling, as we sit beneath his giant pair of balls. "One should actually talk about it and not stop talking about it – we're in a very prudish time, things are getting more prudish by the years. The world is totally sexualised, but only for marketing purposes. Free sexuality, free of charge and free of control is seen as very dangerous. I think one has to treat sexuality with honesty, and acknowledge its importance. We wouldn't exist if it wasn't for the sex drive."
Male sexuality is one of the few visible trademarks from Tillmans' early work that endures in the new show. Close-up shots of the arcs of men's necks, a candid portrait of Frank Ocean in the shower and a video of Tillmans himself dancing in a hotel room all speak directly to the photography that he used to shoot for magazines like i-D in the 1990s, when he was living as a young artist in London. These were editorial images, capturing subcultures and people with no apparent place to be. Despite this work, and despite fast becoming the most fashionable photo artist to namedrop at the time, Tillmans was never too interested in the fashion world; he aspired towards the institution, and in 2000, when he was 32, he successfully crossed over, becoming the first photographer to win the Turner Prize.
Tillmans received a major retrospective at Tate Britain in 2003, showing all his work to date. Now 48 years old, he's having his second Tate solo show. What has he done to deserve another retrospective so soon, I ask. Tillmans is humble: "As an artist, this is one of the most important things that can happen to you in your life – they don't come much bigger," he says. "The premise of the exhibition was to reflect all the different media I use and language I employ now. That was really the reason why [curator] Chris Dercon proposed a second show at Tate after just 14 years. There had been so much new development we thought it would be interesting to reflect, to show that art-making is of course not bound to traditional 2D or 3D media."
The show plays with technology; there's the super-high res blown up social documentary work, the abstract manipulations of analogue photo development and the "Playback Room", which invites visitors to sit and listen to pop music on proper audio equipment, at the same quality you'd expect from a professional studio. The sweeping 14 room gallery show is just one part of the programme, though; Tillmans will also be curating a series of sound performances in the Tate Tanks this spring. One is a sound dissection of the Pet Shop Boys' "It's a Sin", with Tillmans playing the record layer by layer (there are 48 tracks in total) over the course of a few hours.
The "2017" show was always about doing something experimental, the artist explains. "That was a huge liberation from the start – that, no, this doesn't have to be a retrospective, there is no Concorde here." Although he loves the 90s work "dearly", "2017" is about "what you cannot see in the world – in the net or in books – which is the experience of being in front of individual prints but also being in these spaces". He describes the show as an installation, almost: "What I look at when I install is the sound, the many different frequencies in the room." He also explains that the show really doesn't have much to do with the year 2017. "Calling it 2017 at the beginning of the year is of course a contradiction, because you would assume there was something of 2017 in the show, but there can't be. And the catalogue people were of course worried – they thought, 'Oh, we can't sell the catalogue in 2018,'" he laughs.
If, as he approaches 50, Tillmans is still playful, still a contrarian and his work still successfully captures the essence of youth culture (I mean, what could be more zeitgeisty than Frank Ocean in the shower?) he admits he's done a lot of growing up, too. Last year he became the art-world poster boy for the Brexit Remain Campaign, designing T-shirts with stay slogans, and speaking publicly about his grief over the result.
"I think it was definitely the biggest thing that I have experienced in my life, as a moment in history," he reflects. "Of course the fall of the Berlin Wall was a total historic sea change, but if you think about the Western world, post-war, what is going on now is the biggest upheaval. Our free, liberal way of life is under full on attack at the moment, and I feel extremely worried. There are forces all working together, even if they seem opposed; Islamists hate gays and are anti-women, Putin wants the woman back at home and hates gays, far-right Americans hate gays and they hate Hillary because she's a woman. It's a vengeful tide," he says solemnly.
Tillman's "Truth Study Centre" – part of the new Tate exhibition – reflects on how he's feeling about politics right now, which is that there's a desperate need to cut through the noise. Made up of cabinets with newspaper clippings and other ephemera, it looks to juxtapose different fallacies and absolutist claims about current affairs through collage. "I started that in 2005, and at the time I called it 'Truth Study Centre', with a pinch of salt – the name is big and grand," he says. "It's not ironic, but it is aware of the impossibility."
Twelve years later, we need a Truth Study Centre more than ever, says Tillmans. "I feel like, at this point, we have to move forwards. We can't just say, 'Oh, isn't it crazy, this world, this post-truth world?' We have to go beyond this quickly now. How can we fix the backfire effect?" Posting something online is not enough, he says: "One has to join parties and movements and groups and be present at votes."
The "Truth Study Centre" might be about uncertainty, but it's still hard to believe Tillmans is the artist who once said the unifying thread in all his work is doubt, while in person he seems unerring in his beliefs, unabashed about sexuality, passionate about politics. Has he in fact gained the gift of certain certainties, I ask, as we walk out the exhibition on the day before it opens to the public. "If I say 'yes' it's already defeating the question, because it would mean I know the answer," he replies. "Doubt can only be genuine when it's not theatrical doubt."
That's not an answer, I point out. "The danger [of this exhibition] is of course huge," he concedes. "The feeling that I have to be complete, that I have to show my best work, that all the big hitters have to be here – it could leave me like a rabbit in the headlights. But I have to trust that after almost 30 years of practice I know what I'm doing. I have to trust it's not complete rubbish."