By Tim Bowler
BBC World Service business reporter
Models of landscapes were built and then drawn
One of the world's biggest sales of cartoon art has opened in London - and taking centre stage are the comic strip adventures of the science fiction space pilot, Dan Dare.
Dan Dare and his friends were hugely popular throughout the 1950s in Britain. Much of his success was due to the brilliantly inventive artwork of his creator, Frank Hampson.
While Dan eventually went on to star in TV cartoon shows and radio series, Frank Hampson's art itself was not commercially valued.
But this has now all changed. Single pages of his original drawings are now selling for up to $15,000.
Besides the brilliant colours, it was the inventive way Frank drew the strip which inspired many fans.
Chris Beetles, the owner of the central London gallery where the comic art exhibition and sale is taking place, explains how popular the adventures were when they began more than half a century ago.
"I can remember the excitement, I can remember everybody clustering around when I got it, saying, 'Me next, me next'," he says.
"You saw it in the newsagent's and had to pick it up. You saw it on a desk and had to pick it up."
Interestingly, Dan and his companions deliberately weren't portrayed as superheroes.
Rod Barzilay, the editor of Spaceship Away - a comic dedicated to publishing new Dan Dare stories - says: "They got tired, they got hungry, they made mistakes. It was just by working together as a team they would get through problems, and you could identify with that."
At a time when post-war Britain was still in the grip of rationing, and most comic strips were in black and white, the Dan Dare strip in the Eagle comic was an instant hit with readers.
Each week, Colonel Dan Dare, a pilot with the International Space Fleet, and his faithful companion Digby, would zoom into space to do battle with their arch enemy, the Mekon.
Luckily for Dan, the Mekon's dastardly schemes usually failed.
In his gallery, Chris Beetles is keen to point out the lush, rich landscapes that Frank Hampson created for the very first Dan Dare story.
"You can see the artwork just fills the room, with all the vibrant colours that he used.
"There's a huge panel showing how beautiful the world of Venus is, this couldn't be any more exotic and it is beautifully drawn. It's very lush and exciting, it's as though we've encountered Shangri-La," he says.
He is not surprised at the prices Frank Hampson's artwork now commands.
"This is a marketplace, there are so many people who want them and there are so few originals left. These are the only remaining panels from the great first story, and there aren't any more."
Dan Dare stories are to be reprinted 50 years later
Yet all this success came at a price. The comic strip had a punishing production schedule.
One of the team recruited to help Hampson was artist Don Harley, who says they regularly worked long hours to meet the deadlines.
"In a normal week, I would come back in the evenings as well - but when we really got behind with the work, it meant working all night for possibly two days," he recalls.
Frank Hampson was also one of the first artists to draw his comic strip from life. Models of spaceships and alien cities were all painstakingly built.
Don Harley says everybody got involved: "The artists themselves posed for photographs, based on the roughs that Frank Hampson drew. Dan's uniform, for instance, was based on Frank's old army uniform."
While the originals might be too costly for many people, the stories themselves are now being republished.
Nick Jones of Titan Books says this was largely due to the quality of Frank Hampson's work: "His artwork is extraordinary, and it still inspires comic artists today."
For his fans, Dan Dare offered a hopeful image of where humanity could end up, with a world government, nuclear disarmament and easy space travel.
The future might not have turned out quite as Frank Hampson imagined it, but as far as prices for his artwork go, the sky certainly does seem to be the limit.
Or as Dan's faithful assistant, Digby, might have put it: "Suffering satellites!"