You can cut into John Piper’s career anywhere, as one does with a pack of cards, and always, it seems, there is something fresh and interesting to find.

The range and fertility of Piper’s interests is impressive. Whereas many artists, once their signature style has been established, stay on track, single-mindedly in pursuit of a clearly identifiable career, Piper took risks and remained open to diversions.

By the mid-1930s he had earned himself a distinctive role – his abstracts defined him as one of England’s leading modernists. Many would have been content with that. But Piper, troubled by the growing emphasis on pure form in modernist art, during a period darkened by worsening international relations, began to let in other interests.

A meeting with John Betjeman brought him a commission to write a Shell guide to Oxfordshire, and between May and September of 1937, instead of keeping his eye on what was happening in Paris, then the cultural centre of Europe, he spent many days trawling through this county’s villages and small towns, jotting down notes on landscape, churches and even forgotten backwaters, for the information needed for his gazeteer.

Still more surprising to the modernists with whom he had been affiliated was his sudden infatuation with the antiquated medium of aquatint, again stimulated by Betjeman, who collected late 18th- and early 19th-century travel books, often illustrated with this medium. Piper turned it on Brighton, and published in 1939 a volume of prints called Brighton Aquatints. It caught the attention Osbert Sitwell, an authority on Brighton, who praised it highly in a full-page review in The Listener (14 January 1940).

But Piper’s former colleagues and admirers, among them Ben Nicholson, Barbara Hepworth and Herbert Read, were nonplussed. They looked on Piper as a turncoat and a traitor to the modernist cause.

Yet Piper’s commitment to the modern remained evident in almost everything he subsequently did. And his familiarity with the language of abstraction continued to inform his many designs. Nevertheless, the approach and onset of war confirmed him in his understanding that International Modernism, with its idealist philosophy, was out of touch with the angry melancholy of the wartime mood.

Instead, he sought inspiration from the romantic element in English art, and sought to revive native traditions in modern terms. This was a man whose career moved with the times. His interest in architecture made him useful to the ‘Recording Britain’ project, and this in turn led on to commissions from the War Artists Advisory Committee.

But when in 1940 he was invited to paint ruined churches, he at first hesitated to accept this commission, until a telephone call from Kenneth Clark sent him to Coventry the morning after a raid which, lasting eleven hours, had destroyed two-thirds of its city centre. Instructed to make a record of its cathedral, he discovered that this great medieval building had overnight been turned into a blackened, calcined, roofless ruin – and he understood fully that it was not just stones and mortar that had been destroyed, but also history, memory and human associations.

If Piper’s art is open to meanings and allusions that reach beyond the aesthetic, he is also renowned for his ability to rework his interests and ideas across a variety of media. John Piper: The Fabric of Modernism looked at the way his interest in modernity extended into the field of textile design and into tapestries, as well as ecclesiastical vestments.

They are a part of his active involvement with what he called ‘delegated art’. He chose the word ‘delegated’ because of the trust that an artist, as designer, must place in the maker, when handing over to a craftsman or craftswoman a design, say, for stained glass or a textile or tapestry.

Piper readily placed his confidence is those he knew had sufficient knowledge and experience of their own craft, not to copy the artist’s ideas, but to translate them into a new medium, making adjustments and changes as and where necessary.

The chief example of this is his hugely fertile working relationship with the stained-glass maker Patrick Reyntiens. Few artists can boast of such trust, and some actively dislike others interfering with their designs in this way. Piper, however, had great respect for craftsmanship.

After producing his final design for a theatrical back cloth, on a sheet of paper measuring, perhaps, no more than 10 by 14 inches, he found it incredibly exciting to see it translated into a 100 ft-wide stage curtain, with certain colours enhanced or dimmed according to the needs of the theatre’s auditorium.

Previously, attention to Piper’s textiles and tapestries has been underplayed. This exhibition, with its rich display of exhibits, offered new insights into these two fields, as well as his achievement with the design of vestments and in the use of mosaic, in tables and for wall decoration.

With the textiles, it is especially fascinating to see how Piper managed to reuse motifs from his paintings and prints without these images deadening the necessary flow of the repeat. The Sanderson fabrics, in particular, excel at recreating the painterliness of John Piper’s designs. They must surely represent a high point not only in the manufacturing of textiles but also in the history of artist’s designs for industry.

Occasional Piper erred. When Walter Hussey left St Matthew’s, Northamptonshire, to become Dean of Chichester, Piper designed for him a cope. Ornamented with bold appliquéd shapes that pay homage to the ecclesiastical vestments made by Matisse, the cope must have introduced a modernist note into liturgical processions. But it had been made by a theatrical costumier in materials unsuited to repeated use and which also made the vestment heavy to wear.

Soon after completing Hussey’s cope Piper accepted a commission to design whole sets of vestments for each and every period within the church year for Coventry Cathedral. In this instance, he spent a great deal of care on the precise choice of coloured silks, and worked with Louis Grosse, a Belgian specialist in ecclesiastical vestments, whose tailoring gave to everything made in his workshop a perfect fall and grace.

Subsequent vestments, as can be seen in this exhibition, were made for Chichester Cathedral and for St Paul’s Cathedral. Behind them all lies Piper’s experience of having designed for the stage, for plays, ballets, and for Benjamin Britten’s operas, for this had given him an understanding of how to use colours and shapes that would carry across great distances, as is necessary in the spaces associated with cathedrals.

This exhibition was timed partly to celebrate the 50th anniversary of the unveiling of the seven-panel tapestry which Piper designed for Chichester Cathedral’s sacristy. Again, this was a commission to which he brought an informed awareness, this time of both ancient and modern tapestries. It is evident that he wanted a less static orchestration of motifs than that found in Graham Sutherland’s enormous tapestry for the east wall of Coventry Cathedral.

He and Hussey were both aware that the sacristy at Chichester was somewhat cold, dim and dark, and in need of something that would attract and warm the eye. It took a while for some church-goers to become comfortable with Piper’s strong colour chord, of purple, green, red and blue, within the low-key hues of this ancient building. Again, the creation of this tapestry was enhanced by Piper’s decision to work with Pinton Frères in the small town of Felleton, which had a close historical association with Aubusson tapestries.

To visit the tapestry workshop at West Dean, where some of his later tapestries were produced, is to gain insight into Piper’s understanding of this medium. His desire to merge one colour into another was here achieved by the gradual alteration in the coloured strands, sometimes up to seven in number, that make up the yarn.

Ironically Piper, who valued spontaneity in art, here engaged with a medium that is slow in production, requiring much time and labour (unless directed digitally, by computer, as is the case with Grayson Perry’s tapestries, which noticeably lack the subtlety of colouring that Piper achieved in this medium).

Chichester has been fortunate in its association with Dean Walter Hussey and, through Hussey, with Piper. It is very apt that this exhibition celebrates the 50th anniversary of Piper’s tapestry for the Cathedral’s sacristy.

Michael Northern, the lighting director who worked with Piper on several theatrical productions, was careful never to employ direct lighting on his sets, for he was aware that Piper handled colours in such a way that their effects naturally spread. The same care in lighting is required for his tapestries. In the sacristy, the need to focus light on the altar and on the celebrant of the mass is critical, but if direct lighting is also focused on the tapestry, its effect is slightly damaged. But even when overlit, this tapestry remains the most outstanding example of Piper’s ‘delegated art’, and few today would deny that, with its warmth and vitality, it does important service to the Cathedral.