Black on Maroon, 1958, Mark Rothko, Tate Modern, London
"As a teenager, the room of nine of Rothko's Black on Maroon paintings seemed like an explosion of sexy, messy modernity.
I still feel a thrill whenever I see them today. They're as gorgeous as they're sinister, but even more thrilling is the memory of first discovering them. I didn't understand what I was seeing, which made them all the more tantalising."
Tom Phillips, Artist, Slade Professor of Fine Art, Oxford University
The Snail, Matisse, Tate Modern, London
"I think that this painting answers the question that Matisse asks when he says that anybody can paint with two colours, some people can use three, but bring in a fourth and you have to be really good at what you do.
It's a collage really, using cut-out pieces of paper which are coloured, and it's also a classical piece of abstract expressionism.
It's not about anything, it doesn't describe anything. Matisse was playing on the whole surface, the whole field - it's a game piece. It was produced late on and backed by instinct. It is a hard game of dice played by a master."
Deborah Swallow, Director, Courtauld Institute of Art, London
A Bar at the Folies-Bergère, Edouard Manet, Courtald Gallery
"Manet was challenging in presenting women and bridged the gap between classical traditions and painting modern life. He was a breakthrough artist: a champion of realist modernism who was criticised for breaking the mould.
Manet was challenging conceptions of representation and he was also challenging the conventions of the world he was living in at the same time.
Today we are used to multiple perspective - seeing the same image from different angles. This was not so when Manet was painting, and in this painting he switches reality through the use of the mirror.."
Jacob Simon, Chief Curator, National Portrait Gallery, London
Henry VII, 29 October 1505, artist unknown, National Portrait Gallery
"Visually, this is a stunning duel of a portrait; Henry starts forward at the viewer from the parapet wearing the red robes of Lancaster, his hands on the ledge. It is immediately exciting and emotive. Henry VII was looking for a new bride and this was painted to be sent to the court of Maximilian to present him with a portrait of what Henry looked like. So we know almost everything about this painting.
Portraits of Richard III, in comparison, are stiff and remote. Henry VII's portrait speaks in a very particular way. His eyes look at one. He is a Renaissance man but, at the same time one sees a shrewd, wise and wily man who throughout his reign managed to amass the fortune of the Tudor dynasty."
Meredith Etherington Smith, Editor-In-Chief, Art Review and Christies Magazine
The Archers, 1769, Joshua Reynolds
"First, it's a masterpiece of great British art. Secondly, it's a wonderful, interesting composition. The relationship between the archers is most unusual. Thirdly, in a curious way it's very modern, it is romantic in a curiously English way. I saw it for the first time in Christies magazine, on the front cover. I just instantly fell in love with it. It has a wonderful quality of Englishness.
It is a wonderful rhythm of a composition; the two archers in unusual pose, the leafy background. It is the overall composition that I find most fascinating. When one looks deeper into the painting, it becomes exquisite. This is when paint goes beyond paint on canvas and sets up a force field of atmosphere."
Michael Tooby, Director, National Museum and Gallery, Cardiff
Black on Maroon, 1958, Mark Rothko, Tate Modern, London
"My favourite painting is Simone Martini, Christ Discovered in the Temple. But in particular I am interested in using the word 'greatest'. The Martini is 6 inches by 9 inches, whereas the Rothko is something like 12 feet by 8 feet. The vastness of Rothko is something that you might say creates a different sense of 'greatest'.
"The vastness makes you think of the trivial and the everyday in the context of the sublime and greatness. I think that by bringing Rothko's work to its Tate room creates a wonderful dichotomy between the great and the simple and the trivial and everyday bustle. In both the Rothko and the Martini is the humanity and the ordinariness and the eternal that is in great art."
Neil MacGregor, Director, British Museum
Vase of Flowers, Jean Baptiste Chardin
"I chose this partially because it's just so appealingly small. That may sound strange, but I enjoy the fact that I can easily imagine holding it. If it was mine, I could prop it up on my desk rather than hanging it on the wall.
I also enjoy the fact that I'm able to imagine I painted it myself. You can clearly see the mark of the artist's hand - thick strokes of the brush, generous daubs of paint - and so you feel close to him. It actually looks like a painting. Many paintings don't. More photographic-looking pieces don't always appeal so much to me. With Vase of Flowers, you know it was made by a human.
I remember travelling to Edinburgh, at the age of 13 or 14, and discovering it. It's got such an immediacy to it. Just all those dabs of colour ... wonderful.
Robert Buchanan, Winner, Beck's Futures Prize and Spirit of Scotland Prize
James VI and I, 1618, Paul Van Somer, Royal Collection, Holyrood
"This work made a huge impression on me. Works of art often lose their power as soon as they're placed in a museum. This painting is where it belongs - in a palace.
I used to work for an art handling company in New York, and I came to realise how wonderful paintings are as objects. Old paintings last for so long because of the materials used - the oil is so robust, it expands or contracts depending on the heat. They can be rolled up and taken around the world, they'll never die.
Depending on who you speak to, James is either a buffoon or a tactical genius. In this work he looks so stately. The painting was clearly commissioned to convey competency and regality - and it worked on me, 400 years later."
Anna Somers Cocks, Editor, The Art Newspaper
Rokeby Venus, Velazquez, National Gallery, London
'This has a personal relevance for me. I grew up in my grandmother's house in Venice and she was the best 19th century copyist of Velazquez. We had copies of all of Velazquez' paintings in our house except for this one, which my grandmother didn't approve of. It's a painting I've always thought was incredibly beautiful.
One has to think of Velazquez at the court of Spain: It was very stuffy and ruled by etiquette. Velazquez was known as a painter of kings, so to produce this very personal and private painting at that time was extraordinary."
Stuart Pearson Wright, BP Portrait Prize Winner 2001, Now Painting JK Rowling For NPG
Mr and Mrs Andrews, Gainsborough, National Gallery
"Everything about this is mysterious. The two figures have such enigmatic expressions. What are they up to? What are they thinking? And then the landscape is so enigmatic too. It's an agricultural landscape, in the middle of the day, but there's no agricultural workers anywhere to be seen. Where on earth is everybody? What a strange atmosphere the place has, this lost age that can't be returned to."
Timothy Clifford, Director, National Galleries of Scotland
An Old Woman Cooking Eggs, 1618, Velàzquez, National Gallery of Scotland
"What is most striking about this painting is surely its veracity. One gets the feeling that one is looking into a room in which there are no obstacles. Nothing comes between the subject and the observer. The artist here is the perfect observer.
As the centrepiece a few years ago in the National Gallery of Scotland, set alongside many other works from his youth, there was no doubt it is a masterpiece. I think that it is easy for many people to empathise with this painting in one way or another."
Interviews by Michael Connella, Mark Dearn and Clare Huckvale