By the beginning of this week the exhibition of the work of Scottish Colourist FCB Cadell – at what is now officially Scottish National Gallery of Modern Art 2 but most of us call the Dean Gallery – had attracted 25,000 visitors since it opened last October.

Perhaps that does not put the show in the blockbuster category, but it does represent a considerable public interest in one of the most identifiable – and collectable – schools of Scottish art, and recognition for what is an extremely well conceived, realised and displayed show.

When the exhibition closes on March 18, that will not be the last that is seen of it. A selection of 40 works, more than half of the Edinburgh show, will travel to the MacManus in Dundee, where they will be shown from April 6 to June 17. In fact it will be a return journey for half a dozen of the pictures as Dundee Art Galleries and Museums lent five works for the show and the University of Dundee another, but Dundee itself will see those six together for the first time in a decade.

It is even longer than that since the National Galleries staged a major Colourist show, but the Cadell is just the first of a series to seen in Edinburgh, with SJ Peploe following this autumn, JD Fergusson a year later and a Leslie Hunter exhibition at the City Art Centre this summer. If all of them are as revelatory as this first one, the Colourist quartet will have been as well served as they have ever been since the term was first coined in 1948.

Alice Strang, who is curating the National Galleries shows, told me at the Cadell show's opening of her continuing anxiety that she may not have chosen the precise soft grey colour for the walls, echoing the tone of the painter's own studio. That attention to detail is reflected in the careful hang of the pictures, one room dedicated to his Iona work, the corridor displaying self-portraits and the development of the artist's ground-breaking studio pieces carefully plotted.

Guy Peploe, managing director of The Scottish Gallery in Edinburgh's Dundas Street, is already looking forward to seeing his grandfather's work benefit from the same careful approach.

"It was important to address the individuals within the group," he said, "and a good balance has been struck with the relevance of biographical and other information. The chronological hang is not slavish but speaks about the development of Cadell as a painter."

Not only is the SNGMA 2 show a superb survey of Cadell's best paintings, bringing together works from public galleries across Scotland with many rarely seen works in private hands, Strang found room for some of the objects that feature in the still lifes as well as juvenalia and sketchbooks. The letters and other material gathered in the gallery building's library have proved a very illuminating addition to the experience of being swept along by the pictures upstairs.

Not only is it made clear how Cadell arrived at the point in the 1920s when he was creating work in a style that was entirely of his own devising, but "FCB Cadell" the exhibition is constantly putting this in the context of his early decision to make a living by painting. Young Bunty, as he was nicknamed, may have been born into middle-class Edinburgh affluence, but his fondness for the high life and fine things could not be sustained by the sales of his work.

Edinburgh looked after him in his early career, so much of the earlier work in the exhibition – including his first mature paintings of Venice – has come to Belford Road from not very far afield. Later though, it was the bolder taste of Glasgow that promoted Cadell and his cohorts. A Lady in Black became the first Cadell in a public collection when Glasgow Corporation bought it in 1926 for a very respectable £180. The Orange Blind, one of the most popular works at Kelvingrove (although not there currently, obviously) was sold at the Royal Glasgow Institute annual show in 1928 for £150. Glasgow art dealers TJ Honeyman (who would go on to direct Glasgow Art Gallery) and Alexander Reid and then his son AJ McNeill Reid championed his work: it was the Reids who first gathered together the work of the painters who would become known as the Scottish Colourists for shows in London and Paris. His private patrons – and there is some evidence that Cadell's life-long practice of working in that way rather than entrusting his output to a third party may not have been to his financial benefit – included Glasgow shipowners George W Service and Ion Harrison.

That this information is all clearly conveyed in a show of paintings without it seeming like a history lesson is a seductive achievement. It is impossible to spend time looking at the work – and Cadell's best paintings are very fine indeed – without also acquiring a picture of the man.

It is clear that he was gay, but that is never laboured. A single, somewhat perfunctory, faceless female nude is completely upstaged by two striking naked male figures, a white male boxer and a black man, whose image would have been in the vanguard of bold subject matter in 1922. Cadell's long friendship with Lady Sybil Campbell of Argyll was founded on his close relationship with her son Ivar, lost in the First World War. From the 1920s to his death, the painter's constant companion was Charles Oliver, a friendship begun during that same war, in which Cadell served as Private in the kilted "Dandy" ninth battalion of the Royal Scots before accepting a commission in the Argyll and Sutherland Highlanders. The simple, graphic, cartoon-like work he produced at that time is also included in the show and illustrates what a versatile and complete artist Cadell was, but it is also very camp.

Alice Strang's exhaustive researches produced plenty of insights into the youngest of the Colourists, and Guy Peploe is expecting that even he may learn more about his grandfather from the next show in the National Galleries' Colourist sequence. With still life as Peploe's most persistent subject, the display of objects "to show how ordinary they were – not things of great value" (as Peploe puts it) will be an important inclusion.

"I hope they do a similar job, full of detail and sketches, with the best works from public collections balanced with works that will be seen as rediscovered, even if they are known by me."

He adds that there are still "lost works" which appear on the market from time to time – and autumn's outing for Peploe could be the event that prompts more of them to resurface.

The Scottish Colourist Series: FCB Cadell is at Scottish National Gallery of Modern Art, Edinburgh, to March 18.

The Scottish Colourist Series: FCB Cadell –Selected Works is at The McManus: Dundee's Art Gallery and Museum from April 6 to June 17.