Last updated at 13:08 02 February 2008

They may look like pin-sharp photographs - but these amazing pictures are actually drawings created with the humble ballpoint pen.

The stunning pictures, measuring up to 10ft high, were drawn by a rising star of the art world, Juan Francisco Casas.

Casas, 31, can use up to four 14p ballpoint pens for a canvas and his works are already a sell-out at exhibitions.

Formerly a traditional painter, Juan began the drawings three years ago based on photographs of nights out with his friends.

Scroll down for more...

Speaking from Rome yesterday, he said he admires the "simplicity" of the ballpoint pen, invented in 1938 by Hungarian Laszlo Biro.

Casas said: "I guess it started off as a joke, to try and make something so realistic that people would think is a photo.

"I also wanted to create it with something that everyone has - a Biro. I don't think it has ever been done before.

"For me it's not that different from painting. I was trying to show that it doesn't matter what material you use, it's what you do with it."

Casas only uses blue Bics and can get through several to make one drawing.

He has just spent two weeks drawing his largest piece, which is 10ft high by 3ft wide.

The only drawback is that he can't erase any errors. He said: "Mistakes are the main problem. It's better if I make them at the beginning."

Scroll down for more...

Casas studied Fine Art at the University of Granada, in southern Spain, and then worked there as a teacher for six years.

He submitted a ballpoint-pen drawing to a national art competition in Spain in 2004 - and was shocked to be awarded the second prize.

He said: "It's a very serious, and academic sort of competition, and I knew they would think my entry was a joke. It was just on a normal piece of paper in biro.

"I had previously done painting - oil on canvas - and this was something new. But they liked it, and it went from there."

Scroll down for more...

He has exhibited in Chicago and in his native Spain, and is preparing an exhibition in Rome where he now lives.

At an exhibition in Madrid last week he sold 60 works for between 1,000 and 5,000 euros apiece (£750 to £3,750).

He said: "It was a real shock that it was so successful. I would love to come to England, but at the moment I haven't got a lot of work, as I've sold everything."

A British firm took over the ballpoint pen patent to make them for the RAF shortly after their invention, and the first ones went on sale in the UK in 1946. The Bic pen, a variation on Biro's original design, went on sale in France in 1950.