Meet the original magician of the silver screen

In the run-up to this summer's tentpole movies, cinemagoers will be told that their special effects are unsurpassed. Whether it's the delinquent superhero Hancock (Will Smith) saving the world, the kids back for another adventure in Narnia in Prince Caspian, or the green giant flexing his muscles in The Incredible Hulk, the CGI is startling.

Nonetheless, a strong argument can be made that special effects are less refined now than they were during an earlier, more innocent time in cinema. In the transition to the digital age, there are skills that have been lost, probably never to be recaptured. Meanwhile, certain names, once revered, have been forgotten.

"Everything that Ray did influenced me, and I salute him every day," Steven Spielberg says of the special-effects supremo Ray Harryhausen, who will be discussing his career at the Edinburgh International Film Festival later this month. Peter Jackson and George Lucas are also Harryhausen fans.

There is a certain irony about their admiration for a figure who belongs to a different era and who worked mainly on B-movies. "I destroyed Washington, I destroyed the Golden Gate Bridge, I destroyed New York," Harryhausen likes to boast of such cut-price classics as The Beast From 20,000 Fathoms and It Came From Beneath the Sea. When he tired of knocking buildings down, Harryhausen moved into the realm of myth. Under his guidance, Sinbad, Jason and Perseus – and, in One Million Years BC, a loin-clothed Raquel Welch – tussled with an impressive array of gorgons, Medusas, pterodactyls, dinosaurs and sword-waving skeletons.

The magic of Harryhausen's creations lay in their creaky, old-fashioned purity. His gods and monsters weren't digitally created, using a click of a mouse. They were handmade. As a kid growing up in California in the 1930s, he fashioned his first dinosaurs from garage bric-a-brac – joints from car rear-view mirrors, old flexible lamps, rubber, wood, corrugated iron, anything he could lay his hands on.

At least Harryhausen's work has been credited by big-name admirers. Who remembers Walter Percy Day? Even among the most devoted fans of old British films, the name of "Poppa" Day has little currency. However, if you've seen his work, you won't easily forget it. Day wasn't a stop-motion animator like Harryhausen; his genius lay in process shots and painting miniatures and backdrops, matte photography and split screen. It was thanks to him that the flying horse carrying the Caliph gallops off into the sky in Alexander Korda's production of The Thief of Bagdad.

"Poppa was the greatest trick photographer and double-exposure merchant that the movies have ever seen," the British director Michael Powell wrote in his autobiography, A Life In Movies. He likens Day to Jules Verne for his powers of invention.

It is easy to see what prompted his enthusiasm. Largely thanks to Day, Powell and Emeric Pressburger were able to recreate the Himalayas... in the Home Counties. Black Narcissus (1947), Powell and Pressburger's Technicolor adaptation of Rumer Godden's novel about sexually repressed nuns, was almost entirely made at Pinewood Studios. (The shots of luxuriant flora were filmed at Leonardslee Gardens in Sussex.)

"What about the Himalayas? You can't build them," the bemused camera operator Chris Challis asked Powell before shooting. Powell told him not to worry: "Glass shots. Poppa Day and his two sons will paint them."

It is hard to imagine the visuals on Black Narcissus being improved on if the film was to be remade today. Technology may have improved, but the artistry of the technicians has not.

However, even in 1947, Day's contribution was being overlooked. The film won an Oscar for its cinematographer Jack Cardiff, but even he questioned later whether the award might more properly have gone to Poppa Day. An artist by training, Day ("a scruffy, bearded wizard," as Pressburger's grandson Kevin Macdonald called him) always saw his work in film as a secondary calling. He'd far rather have been exhibiting at the Royal Academy.

"He [Poppa Day] saw cinema as something ephemeral, as popular entertainment and that was that," recalls his granddaughter Susan Day. She remembers her grandfather as "an absolute tyrant" with a strong streak of eccentricity. "He was a typical Victorian. He felt children should be seen, not heard. We were all terrified of him."

When Korda tried to give him a pay rise, Day demurred, saying that he didn't want any more money. "A typical artist," Susan Day sighs as she recalls the impracticality of Poppa Day, who died in relative poverty.

He was called "Poppa" because he worked with an apprentice, Peter Ellenshaw, who later became his stepson. Ellenshaw, who died last year, aged 93, had been working as a mechanic, but after being taken on by Poppa Day he became a titan of the special-effects world, spending more 30 years as Disney's wizard-in-chief.

Arguably, the best special effects have more to do with imagination and dramatic flair than technological prowess. Georges Meliès (1861-1938), cinema's first special-effects wizard, fully understood that. His 1902 film Trip To the Moon, one of the earliest sci-fi movies, still seems magical. Meliès plays the lead. The most famous scene shows his rocket plunging into the face of a very viscous moon and then crashing into what appears to be a forest of entrails. (The sexual subtext seems deliberate.) The effect is crude, but so playful and surreal that it still has the power to enchant audiences. It is outer space as if imagined by Terry Gilliam.

Besides, who needs CGI when you can rig up an actor with a false chest and hide plenty of animal offal behind it? This was what Ridley Scott famously did on Alien for the scene in which John Hurt's guts explode and the succubus-like alien emerges.

"We had to make it totally repulsive and yet scary as hell," Scott recalled. Movie lore has it that the rest of the actors hadn't been briefed beforehand. The reason they looked appalled by Hurt's stomach troubles was that they were as surprised as the audience would be.

In the heyday of the silent epic, film-makers such as DW Griffith, Cecil B De Mille, Fritz Lang and King Vidor could contrive effects that make even the best efforts of Michael Bay and Jerry Bruckheimer look puny. What they offered wasn't computer-generated armies composed of lookalike soldiers but sheer megalomaniacal scale. They built cities, recreated lost civilisations and staged battles with huge armies of extras.

Meanwhile, the original visual and special-effects supervisors weren't just technicians – they were real artists. Harryhausen underwent a lengthy apprenticeship after seeing King Kong at Grauman's Chinese Theatre in Hollywood in 1933 and deciding he wanted to be a film-maker. There was more to stop-frame animation than just clicking away at home-made models with a camera. He had to teach himself many different skills – "how to draw, how to cast, how to sculpt, how to paint the backgrounds, how to photograph them properly". (He may have spent most of his career making rubber monsters, but, in his way, he is as versatile as any Renaissance craftsman.)

As described by Harryhausen, visual effects were often the most painstaking and lonely part of the profession. Today, at leading visual-effects companies such as Framestore, Cinesite and Double Negative in Soho, there will be armies of technicians beavering away together on films like Harry Potter or The Golden Compass. For Harryhausen, it was very different. He was still busy with Clash of the Titans (1981) a year and a half after everybody else had gone home. It took him five months to match the animation with the live action in a famous sequence from The Valley of Gwangi that sees cowboys lasso a dinosaur. And getting a pterodactyl to fly off with Welch in One Million Years BC was no easy matter.

"I preferred to work alone because you have to concentrate so hard when you are animating," he told me. "Take a figure with seven heads, like the Hydra. You have to concentrate very heavily to remember that the third head from the bottom is going forward, not backward, at a certain moment. If you get it wrong, you ruin the whole appearance of what you are trying to do."

Harryhausen's models look small and harmless – almost like ornaments – when seen sitting on a mantelpiece. On screen, his feats of prestidigitation could transform them into awe-inspiring figures.

In the days before CGI, there was a line that could be traced all the way through film history. Poppa Day had worked with some of the leading names of the silent era. He, in turn, passed his secrets on to a new generation of artists, among them Charles Staffell, who worked on everything from back projection on Powell and Pressburger's A Canterbury Tale to optical effects on Barbarella, Batman and the Bond films and rear projection on Stanley Kubrick's Eyes Wide Shut. (In the 1960s, Staffell was given a special Oscar for developing a reflex background projection system for composite cinematography.)

Day's stepson Ellenshaw was also an Oscar-winner, for his eye-popping effects on Disney's Mary Poppins. "Don't spend long up there. They've not come to see you. They've come to see the stars and the directors," the organisers whispered to Ellenshaw as he waited to go on stage to pick up his award – a remark that sums up the contempt that special effects artists have had to endure.

We like to think that the effects in today's films are far more sophisticated than anything before. In Hollywood, the hype is about 3D and "performance capture". The industry is waiting to see whether James Cameron's phenomenally expensive ($200m-plus) Avatar, due out late in 2009, is as mind-blowing as the studio bosses hope it will be.

It's easy to forget that the artistry lies not in the equipment but in how it is used – and there's nothing to suggest that today's visual-effects artists are any better than Meliès, Harryhausen, Day, Ellenshaw and the other pre-digital magicians.

Ray Harryhausen talks about his career at the Edinburgh International Film Festival (www.edfilmfest. org.uk) on 25 June; 'The Thief of Bagdad' is available on DVD from Criterion