The sound of Electronic Music Systems' VCS synthesizer pervades Dark Side Of The Moon. For a short time the British company's synths, designed by Peter Zinovieff, rivalled the American Moog. Pink Floyd bought an early example of the company's second model, the Synthi-AK; it would become crucial in the creation of several songs including On The Run and Time.

While tremendously versatile, VCS synths were notoriously difficult to programme compared to the user-friendly MiniMoog. Floyd repeatedly owned their example for over a year before they discovered it could actually play notes.

"These inventions were never used in the way they were intended..." [Roger Waters]

While the new music of the early '70's inspired most sleeve artists to increasingly surreal extremes, Hipgnosis, Floyd's design team, kept their feet firmly on the ground.

For Dark Side's two predecessors, Hipgnosis had presented a cow (Atom Heart Mother) and an over-sized human ear (Meddle). The new works' cover would be similarly prosaic: a diagram of light passing through a prism that could have been borrowed from any physics textbook. But the technically simple cover cleverly offered clues and signs to the spirit of the music within. Cast on a jet black background, the design also a triumph of understatement: enigmatic, minimalist and as cooly hip as the band themselves.

Technically, the cover is a 'mechanical tint lay'. There was no original painting; just a black-and-white diagram with instructions to the printer about colours. The packaging celebrates the band's cult of anonymity. You only reach the name Pink Floyd when you open the gatefold, where the band have a credit as producers. The title of the album appears only on the label. Small wonder that EMI slapped a sticker on the front to flag up to the unwary that this was the Floyd's latest.

Storm Thorgerson of Hipgnosis recalls: " I'd had various conversations with the band about what they wanted on the sleeve. Roger explained the intellectual thrust of the music, the theme of madness - the the madness of rock'n'roll and madness in general". But the main impetus for the eventual design was some blunt advice from Rick Wright. "He basically said, 'Let's have no fucking pictures this time, I'm bored with pictures'. I was quite taken aback because he was so definite about it. But he said, 'We want something smarter, neater, more classy'."

Thorgerson duly reworked a prism and light design that had been offered to Charisma for a new label, Clearlight, but never used. This was submitted to the band by him and his partner Aubrey 'Po' Powell with five other ideas.

Today Thorgerson cannot recollect these, save for one featuring a giant wave and a figure based on the Silver Surfer comin book superhero. But the decision-making process in a side room at Abbey Road was swift and unanimous. "They took all of about three minutes. They flicked through them, then when it came to the prism they just looked at each other, said, 'That's the one. Right we're going back to work now.' Then they went back to the studio."

"I was trying to say, Hang on a bit. I thought they were being hasty, because I was keen for them to appreciatte all the hard work that we, as freelancers, had done. I was wanging on but Po, who always had more business sense, realised they were delighted, that we had the gig and that was all that mattered."

Thorgerson's prism proved a resonant symbol. "It represented both the diversity and cleanliness of the sound of the music," he says. "In a more conscious way, it worked for a band with a reputation for their light show. The triangle is a symbol for ambition, one of the themes Roger was concerned with. So you had several ideas coming together. It was Roger's idea to turn the light into a heartbeat inside the sleeve, the sound that starts the music."

Thorgerson designed the front and back sleeves so that the entry and exit beams could be joined up to form a huge shop window display: "It wasn't really a promotional decision, just my egocentric idea - not that anybody ever did it."

The design work was straightforward, so Thorgerson delegated it to George Hardie, the new boy in the studio (now Britain's first professor of graphics). Hardie also created the two postcard stickers included with the album, plus the pink-hued poster of the band (great on the wall if you could get your mum to iron out the creases).

A second poster of the Great Pyramid, shot by Thorgerson on infra- red film, was also included. Today he regrets that a black-and- white time exposure taken at night was not used.

Thorgerson, girlfriend and baby son and Po flew to Egypt for the shoot. But all save Thorgerson got food-poisoning, so he worked solo. Thorgerson and Powell were paid L600 each for their efforts. But for all Hipgnosis' conceptual care, some printers were lackadaisical. In the Soviet Union the album came out with the sleeve printed upside down and back to front.

Thorgerson remains proud of his most famous creation. "It may not have been interesting or challenging as a piece of work but it is interesting as an appropriate piece of artwork for the record. It's either a brilliant piece of art direction or perhaps just a jammy idea - that's for others to judge - but it worked really well in its content."

-The band had done their bit. Now it was time for ground control to take over. And soon for posterity to judge...-

Although Gilmour presents a picture of helter-skelter activity in the Floyd camp during the early '70's, what with all their tours, films, ballets and other commitments, Alan Parsons has a different perception. He says Dark Side Of The Moon took nine months to record - unprecedented for Pink Floyd at the time - in part because of the laid-back pace of work.

"It was very relaxed, even lazy really," he says. "They were already becoming family men. And then at the studio they'd be watching football or Monty Python. Everything stopped for Monty Python. There was never any exuberance from them. They would never be very enthusiastic about anything. It was always, 'That'll be all right.' The only real enthusiasm came from Nick when Jerry the janitor did his dialogue and he said, 'That's absolutely right for this record.'"

"But the atmosphere throughout was good, it was a very pleasant experience for me. There was no friction on a creative level, and the only times things got heavy was when they would argue about business and money. Then they were very heated. Of course, nobody knew the album was going to run out so well or become such a sensation."

At the last, Chris Thomas - favoured for his work on The Beatles' Abbey Road - was brought in as "a fresh pair of ears". "I was brought in at the end of the record, but as a producer," Thomas insists, although his sleeve credit reads "mixing supervised by".

"It wasn't just mixing, it was mixing and recording. For instance, during that time Clare Torry came in to do her thing on Great Gig In The Sky and the dialogue was recorded. Also, on Money, I thought it was such a great riff that I got them tto track the guitars to build it up. In all, I worked on it for about three weeks (Jan. 18 to Feb. 19) with the mixes completed at a rate of about one a day." It was often reported that Thomas was brought in as a third party to sidestep the arguing between Waters and Gilmour. Waters reportedly wanted the album very dry, like John Lennon/Plastic Ono Band, while Gilmour favoured more echo. This is how Gilmour portrayed the situation to MOJO.

He says they were both asked to keep away from the studio to let Thomas finish mixing without further fuss - but that they both slipped back in to "hover at Thomas's shoulder" and continue their heated debate. However, Thomas denies this.

"That's not true," he says. "I know what Dave has said more recently, but there was no difference of opinion between them. At that stage I was putting a lot of echo on all my recordings, and I remember Dave saying at the time of The Wall, You should sue us, because Dark Side Of The Moon would never have sounded like that if you hadn't worked on it. But since then he's always said that he wanted a lot of echo on it and if Roger had his way it would have been drier. I don't remember Roger once saying that he wanted less echo. In fact, there was never any hints that they were later going to fall out. It was a very creative atmosphere. A lot of fun."

Ever since, Waters has subscribed to the idea of handing over the responsibility of the mixing to somebody else, but in the early '70's the specialist remix engineer with his established role in the recording process did not exist.
"It seems the most extraordinary thing to have done now," he says. "I guess it was as if to say, There you are, we've made this very complicated piece and we need someone to come in with a more objective view of all this information. Because it seemed frightfully complicated at the time. Actually, it wasn't very complicated at all by comparison with things we did later on. We did go back in to tweak a bit when the mix was up, but by and large we did very little. What you hear on the recored are Chris Thomas and Alan Parsons mixes."

Although Dark Side Of The Moon developed a reputation as the state of the art in sonic quality and later spawned numerous audiophile vinyl LPs and gold CDs, it was mixed from a second-generation 16-track tape. In some cases the bass and drums were bounced down to stereo on two tracks.

Waters has been slightly dismissive of the sonic quality in the past, but after re-listening to the album recently he says, "I was staggered by a number of things about it. How loud the sound effects and extraneous voices were, which I think is great. The length of some of the introductions, particularly on Time, which goes on forever."

But as soon as the finishing touch was applied on February 1, 1973 - eight weeks before the album's release - Waters suffered no doubts about the quality of Pink Floyd's achievement. "I can remember finishing it and thinking it was fabulous," he says. "Then when it was released I was very pleased and a bit smug to have that reinforced by the fact that a lot of people went out and bought our records before Dark Side Of The Mooon." "Now, I think its enduring appeal comes from a combination of different factors. It is very listenable. I think that is has a certain philosophical and political integrity that comes through, naive as it may be. I think that is important to people. You know that we meant it."

"Then there are a lot of things on it that you recognize - you only have to hear them once. The second you hear it again you cannot mistake it for anything else. That's very comforting for us, the audience. Although it wasn't the first of its kind in terms of the concept record idea, maybe it was the first one that had a heart."

"My motivation has always been to tell my truth in my own way as powerfully as I can, and in a way that's where I have parted company from my ex-colleagues. They are not interested in that - even at the point they never were. I remember reading interviews at the time with Rick saying, 'We don't really care about the lyrics.' And they didn't. And I rather did, and all my records since then have been quite true, always been what I felt."

"Still, they were very happy times. We discovered what we did, each of us, what our contributions were. We had gelled as a group, we were working very well together and we were working very hard, doing lots of gigs. We were in the springtime of Pink Floyd when it was all good fun and we had a common purpose - we wanted to be populaar, we all wanted to be rich and famous and we weren't yet."