Annie Freud (above) on Lucian Freud

I simply love that painting. Great eyebrows, which unfortunately, I’ve lost; I was 14 then. I don’t remember sitting for it, but I know I’m looking at him. Because, you know, it was not quiet. There were moments when he’d ask me to be still, or perhaps not speak, when he was really, really concentrating on something, but we spoke absolutely all the time. I think he knew it would unsettle me if he was too quiet; but also we were just hugely close and had masses to talk about. He used to recite poems and read to me, a lot.

I sat for my father maybe 11 or 12 times, throughout my childhood. It was always very lovely. He used to tell me these terribly exciting stories in which I was the hero, stowing away on ocean liners and jumping from the gangplank on to the ship and hiding, and having adventures; he used to sing and make up little songs for me.

He’d get distressed, and I’d feel I was failing him. You’re young and don’t know who's ­responsible for what

I completely admired what he was doing, always, and was very impressed, looking at important portraits of people and seeing that progress. But I was aware that it was not something I spoke about with other people. I didn’t talk about it with my mother, I didn’t talk about it with friends or important relatives like my grandparents. I knew that it was special and interesting, and that it didn’t happen to all children. The nude he did of me was a pretty tremendous experience. I think it was his first full nude, called Naked Child Laughing. I was about 14 or 15. I felt very much that I made that picture with him. I really, really prize it.

In some ways [sitting] was arduous, because it was a kind of work, and it was very, very tough when he didn’t like what he’d done. He used to lash himself with his brush and jab himself when he was angry, or when he thought he’d done something weak or obvious. He could get very distressed with the way he was working. And I’d feel like I was failing him. Because you’re young and you don’t know quite who’s responsible for what.

As a father, he was quite directive. He wanted me to conduct myself in a certain way. He wanted me to be well seen by other people and people he was close to. He wanted me to have good posture and to brush my teeth and look after myself, and to dress well and look good. He was forming me.

Later on, when I was pregnant, that was a harder experience, partly because it was a night picture and I had to be away from home. I was tired and needy. I was really quite young, and being pregnant is such an all-consuming thing. And also the complexity of the relationships involved, with me, with him, with the other person in the picture. She was the girlfriend, she was my best friend, my husband was missing me at home. There were a lot of aspects of sitting for that picture that were not the easy things I did as a child.

That these paintings are so famous makes me feel celebrated. He very much encouraged my individuality, all during my childhood, and being painted by him was part of that encouragement, to be un-conforming.

Jake Auerbach on Frank Auerbach

Facebook Twitter Pinterest Jake Auerbach in Head Of Jake, by Frank Auerbach, 1997. Photograph: © Frank Auerbach, courtesy of Marlborough Fine Art

For some of the pictures, I know what it was like and what sort of mood I was in, and this picture is certainly one of them. I have a very clear, rich memory of what was going on. There were some big questions at that time, inside my head. I was preoccupied. On a purely surface level, my hair tends to be long or short – this picture of me [in my late 30s] is obviously one of the long-hair periods, which tends to be a four-yearly cycle. There was a crossroads and for me, at least, I think it shows in the picture.

I didn’t see my father from about the age of five to 17, and then when we started seeing each other again, he asked me whether I’d be interested in sitting. I was happy to do it. As you might imagine [as a teenager], I could have bailed at any point, but I never have. I’ve lived abroad a couple of times and it’s not always been practical for me to come back and sit; but if I’m in London, on Tuesdays I sit for my father for about two hours.

Facebook Twitter Pinterest Frank and Jake Auerbach in 1978. Photograph: © National Portrait Gallery, London

Being still for two hours is not nearly as tough as being still and standing up. Real heroes agree to stand for portraits, not sit for them. But I have no intention of ever doing that. The first half is a bit more relaxed, unless something is looking like it might be finished in that sitting. One tends to know – sitters know – if my father feels like something might be finished. There’s a different sort of energy when you turn up. And in that case, you just sit down and get straight on with it. Ridiculous though it might sound, I do on those occasions try to be as “me” as possible. I try to project me, and put more energy into it myself. Obviously what I’m doing is passive – my main job is to turn up and sit still. But if I think something might be finishing, I will just concentrate more and try to contribute energy. Something like a conversation, you know; if you meet someone that you get along with, you put more energy into the conversation.

One gets an idea of what one looks like as time goes by, and I certainly recognise myself in all of the pictures. But it’s difficult to explain. It doesn’t feel like the same thing being painted over and over again. It looks like different facets, or different parts or ideas around the same thing. Even though the process can be very repetitious, it doesn’t feel it.

One of the reasons I’ve always been happy to continue is that whatever’s going on, in work or life, it’s a little haven of quiet in the week; it allows the mind to deal with things that have been concerning me. It is an enforced moment of quiet, when the brain can get to work. I’ve always found it rather useful.

Lila Nunes on Paula Rego

Facebook Twitter Pinterest Lila Nunes in Swallows The Poison Apple, by Paula Rego, 1995. Photograph: © Paula Rego, courtesy of Marlborough Fine Art

I came to London as an au pair in 1985, to live with Paula and her husband [Victor Willing], because he had multiple sclerosis. Pretty soon Paula would get home and ask me: “Can I do a drawing?” In those days, she didn’t use models. She did drawings and then took them to the studio and did whatever she wanted.

I was happy about being involved in the work. It was a new experience. I was living with two artists, so I knew their work was very important for them. Then I started helping Victor, because he was in a wheelchair, but still painting. I helped mix the paints. They considered me part of the family, in a way. Even when I left to do other things, I was always in contact, especially with Paula. There was obviously trust between us and a connection, because we’re both Portuguese. There were a lot of things we talked about that I understood because of that.

Facebook Twitter Pinterest Lila Nunes and Paula Rego in January 2018. Photograph: courtesy of Lila Nunes

Paula knew she could talk to me and I wouldn’t go and tell everyone else. Also, she can count on me. She’s a person who likes routine and people to be on time. She has worked with other models, too, but I think it’s to do with continuity. I always made an effort to be there, whenever she needed me.

I’m also a woman, so I understand a lot of things. When you’re talking to a woman, and you mention something, you don’t even need to go into detail. You know what that person means. It’s difficult to explain. We have fun sometimes, and then other times it’s very hard work because you’re up there for hours. Sometimes it’s frustrating because Paula can’t get what she wants; she keeps working until she gets there. Things come out that she didn’t expect. I think, in a way, that’s because I’m relaxed: she can go through me and find whatever she’s looking for.

The painting of Snow White, when she’s upside down after eating the apple, was a very hard position. There are others where I was on my knees. Some of them were very demanding, physically. We had more breaks, and a lot of cushions. I really don’t know where my mind goes; I can’t remember.

For The Betrothal, I was sitting and I had lots of cushions. There were positions that I could hold for longer because, for example, if she was working on my face or upper body, I could relax my legs. Or the other way around.

The finished work does surprise me – especially the expressions. When I get up and have a look, I think: “Oh my God, that expression was… Where did that come from?” It doesn’t feel like it was me.

Georgia Georgallas on Euan Uglow

Facebook Twitter Pinterest Georgia Georgallas in Georgia, by Euan Uglow, 1973. Photograph: British Council Collection © Estate of Euan Uglow

Euan Uglow was my tutor. He asked if I would pose for him, but before I said yes, I went to see an exhibition he had in London, and I thought, “Wow.” So I agreed to pose. When I got there, I said one thing: that I wouldn’t take my clothes off. I’ll be damned if I was sitting nude! He didn’t mind at all. He goes, “Why is that?” I said, “My parents will kill me.” I was quite young at the time.

That thing I’ve got on is a football shirt, would you believe. I think it was Manchester United. I turned it into a dress, so when I was sitting, it fitted. He found this shop, God knows how, and I had to go and buy a braless bra, if you know what I mean – without the cups. Then he got me Mary Quant stockings, because he wanted the legs to be shiny. He was quite resourceful in that respect. We got all that done, sorted out the costume, and my hair was quite long. I noticed he did the brown bits shoulder-length. I said: “My hair’s much longer than that”, and he said, “Would you mind cutting it?” So I did.

I posed for five years, nearly, on most Saturday mornings, except when I went away, and he’d get cross because I’d get brown. By the time I finished, the hair was back to its normal length. A typical session would be four hours, with breaks in between. I couldn’t sit still for four hours.

He didn’t talk. He really had to concentrate. Any chatting was done during the break, when it was just normal, having coffee with someone.

I had things to think about – my next painting, even making up poetry – so I never really got bored. I used to go blank or reminisce. I was completely out of it when I was posing. But if you sit in any position for any length of time, it starts becoming uncomfortable. Sometimes I could do an hour and a quarter, then I’d have to say, “I can’t do any more, it hurts.” But it wasn’t as uncomfortable as some. You know the painting where she’s crouched on a table [Uglow’s The Wave]? Now that was a really hard position. She posed for almost as long as me, and was on one day a week. She started having back problems. I mean, it’s a hell of a pose.

I turned down a number [of artists]. One was Lucian Freud. I didn’t like him. I thought he was a bit lecherous. But it wasn’t like that with Uglow – there was none of that. You pose as a professional model.

While I was there, I learned a lot from him, as far as technical stuff goes. He was always generous with knowledge. He didn’t protect his secrets about mixing paint or that kind of thing. He gave me a lot of tips, from painting mediums to making frames. He’d often give me blank canvases to work on, and pigments. He was wonderful like that. We became very close friends, right up until the day he died. I used to do his income tax for him.

Kate Paul on Celia Paul

Facebook Twitter Pinterest Kate Paul (second from right) in Family Group, by Celia Paul, 1984-86. Photograph: Spier Contemporary Collection; courtesy of the artist and Victoria Miro, London/Venice © Celia Paul

I’m the one lying down with my head on the pillow. It’s not often that I have such a comfy position. This was painted at a very particular time and under very particular circumstances. It was a memorial, after our father died in the summer of 1983. My sister Celia sketched out the painting in December of that year, then worked on it over the next two years. It was a long, long process.

It felt like an important thing for us to come together in that time. You’ve got my mother in the centre and then the five sisters grouped very tightly around her. Celia doesn’t show herself. I feel she’s represented by the slant of the canvas that’s reflected in the mirror behind, and of course she’s there in every brush stroke.

We were all very young. I’m struck looking at the painting now; I’m the youngest and I was 21. Celia was only 24 when she started it, and our mother was only 56.

Facebook Twitter Pinterest Celia and Kate Paul in Trafalgar Square, London, around 1972. Photograph: courtesy of Kate Clark-Paul

I started sitting for Celia when I was a teenager. There were sometimes negotiations about it: was I going to go out that evening, or was I going to sit for Celia? Looking at some of the early paintings of me, I’m often reading. When I went to university to read English, I was a bit more keen to say, I can’t just sit there doing nothing.

At the moment I’m sitting for her about once a week, for a new painting, and it will be once a week until the painting is finished. It’s a bit like seasons, in a way, and then we’ll have a pause. So there’ll be a spring painting and then an autumn painting. There have occasionally, in the past, been paintings where we’ve listened to a tape of poetry, or there was one painting where I listened to a recording of Jane Eyre. They’ve always had a special mood for me, sort of imparted by what I was listening to at the time. But that’s quite unusual, and in recent years it’s always been silent. I don’t have a problem with sitting still and just thinking.

The silence is a very lovely and powerful thing, and particularly in some of the group paintings, sitting together in silence is a very companionable and powerful thing to do. And then, of course, we all go and have lots of chats in our break. And then come back again.

[Sitting] is certainly a very strong part of my relationship with Celia, because it’s been so much part of my life since I was young; but we’ve always been very, very close. One begins where the other ends. It seems very natural that it’s something I would do for her. And I really like having that opportunity to see each other regularly. If I haven’t sat for a while, I feel a bit out of touch.

• All Too Human: Bacon, Freud And A Century Of Painting Life is at Tate Britain from 28 February to 27 August.

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