OF ALL art forms, graphic design is the least discussed and least understood. This is paradoxical because graphic communication is at the heart of modern life and there is very little that it doesn’t touch.

Many people have no interest in art and never venture inside a gallery, but everyone encounters and uses the work of these visual communicators every day — in magazines, books, newspapers, television graphics, postage stamps, street signs, film credits, packaging and the internet. Graphic designers shape the form of all kinds of information and their stylistic decisions project powerful messages that influence the way we perceive things and respond, whether we realise it or not.

Communicate, an exhibition that opens at the Barbican Centre this week, tells the story of the most creative and influential British graphic design. The Barbican curator Jane Alison and I decided to start the exhibition in 1960 because this was the moment when graphic designers began their push to become more professional.

A new generation, educated in the 1950s at the Central School of Arts and Crafts and the Royal College of Art, wanted to introduce greater rigour into the gentlemanly field of endeavour previously known as “commercial art”. They saw themselves as visual problem-solvers, and they argued that good design was essential for modern business. Fletcher/Forbes/Gill, formed in London in 1962, was the very model of the trendy new design firm. Ten years later, the partners Alan Fletcher and Colin Forbes went on to found Pentagram, probably the most renowned of all British design companies.

Communicate focuses on individual designers and smaller, independent studios that have made an inestimable, though often undersung, contribution to Britain’s visual culture over the past four decades. Among more than 500 exhibits by more than 100 designers there are many landmarks: CND posters by Ken Garland from the early 1960s protest marches; copies of Oz, the Establishment-baiting underground magazine, which still throbs with graphic energy; two Monty Python books designed in the early 1970s by Katy Hepburn — subversively playful design classics that have never received their due; album covers by masters of the medium such as Hipgnosis, Vaughan Oliver, the Designers Republic and Intro.

If these names are unfamiliar, it’s because most graphic designers are not public figures. Of all the designers featured in Communicate only Neville Brody, who made his name in the 1980s as designer of The Face, and Peter Saville, the subject of a Design Museum exhibition last year, are widely known outside design. Some view their professional anonymity with pride, but many others are increasingly assertive.

One purpose of Communicate is to put names to the creators of so much significant work, and a point to bear in mind is that most of the designs on display are personal in some way. They have been created by individuals with strong convictions who have something pressing to say, or at least an original graphic style. That’s why the work is so distinctive and engaging. The challenge for designers is to find a way of reconciling personal motivations with the needs of their clients, whose messages they are, after all, being paid to communicate.

This explains the emphasis in Communicate on projects for publishing, music and the arts. These areas attract designers because they have a level of content and a degree of connection with a committed audience that purely commercial projects, promoting goods and services, usually cannot match. They allow the designer greater scope for interpretation and for providing an extra layer of interest. Much of the most original British design in recent decades has emerged from here. It has always been rare for book or record reviewers to pay any attention to design, but it’s often a vital aspect that sets something apart from similar items and makes it so memorable. Jonathan Barnbrook’s monster monograph for Damien Hirst and Why Not Associates’ flowing page layouts for a book by the architect Nigel Coates treated the publications as tactile, luxurious objects.

Communicate shows that over the past 40 years design has assumed an increasingly central place in our cultural life. If some of the earlier designs on display, such as John McConnell’s Art Nouveau-inspired identity for the Biba store, now look restrained, it’s because we have become accustomed to a much more lavish approach to design: more colour, imagery, detail and complexity. The public long ago entered into the game of responding to sophisticated graphic signals and anyone who wants a project to succeed in the marketplace must take this visual need into account.

This raises some dilemmas for designers who don’t wish to see their skills applied as Pavlovian stimuli to manipulate a design-conscious public. In 1964 Ken Garland published a design manifesto, First Things First, lamenting the overemphasis in design, even in those days, on essentially frivolous forms of promotion. It was updated in 1999 and a number of British designers included in Communicate signed the text.

The exhibition features work by graphic agitators such as Robin Fior, David King and Lucienne Roberts, who have used the medium as a form of political dissent or to underwrite social causes. Other designers, such as Tomato, Fuel, Paul Elliman and Abake, take the idea of self-motivated design to its logical conclusion and initiate their own projects — magazines, books, short films, typefaces. Some of this work, such as Scott King’s text-based pieces created for the gallery wall, looks a lot like art.

For those who want to preserve the old divisions between art and design, such developments are controversial. But what the exhibition shows is that the boundaries began to crumble some time ago. This has created the possibility of communicating in new ways and all the signs suggest that this is where we are heading.

Rick Poynor is guest curator of Communicate: Independent British Graphic Design since the Sixties at the Barbican Centre, Silk Street, EC2 (020-7638 8891) from tomorrow until Jan 23

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