On Wednesday, when the Watercolours & Drawings Fair opened in London, its organisers must have been hoping that history would repeat itself. Now in a new venue, the Flower Cellars, Covent Garden — formerly the Theatre Museum — the fair is a descendant of a series that began at the Park Lane Hotel in January 1986.

In the days preceding that first opening there had also been heavy snow, so much indeed that some exhibitors had to hire a helicopter to retrieve stock from their conservator cut off in Kent. There were gloomy predictions that the weather would deter buyers, but on the day a lengthy queue had formed an hour before the doors opened.

There may not have been a queue this time, but attendance on the opening day was most encouraging, especially as a good proportion was actually buying. As in previous recessions, the traditional art market is doing well, and works on paper, in particular, have a comfort value as well as holding financial value better than most mainstream investments.

As a very broad generalisation, people who collect works on paper — Old Master drawings, English watercolours, prints and so on — are different from those who collect paintings. Paintings are for the wall, where they are often intended to make statements about their owners. Works on paper may be displayed on walls, if lighting and other conditions are right, but equally they may be brought out from portfolios and boxes, to be enjoyed and discussed with other enthusiasts.

The crowds at this fair, or visiting dealers’ shows in the Master Drawings Weeks (January in New York and July in London) are made up of friends, or at least friendly rivals.

There are several reasons for the emotional response that collectors so often have for drawings and watercolour sketches — they show us the workings of an artist’s mind. In a watercolour an artist cannot make a mistake, whereas in an oil painting he or she can bodge and make over. With prints, the “original” is to be stressed. The prints on offer at a fair such as this or at the London Original Print Fair in late April are not the “limited editions” so splendidly described by Monty Python as being “strictly limited to the number we can actually sell”, but physically limited by the life of a worked plate, and the decision of the artist. Here too there is a personal relationship between an artist, the work of art and the possessor of it.

At the Watercolours & Drawings Fair there are works from £100 to nearly £100,000, suited to a wide range of tastes. In the 1950s and early 1960s English watercolours were unfashionable and sought out only by a small band of collectors — who enjoyed themselves hugely. Fashion changed, and for a while the 18th and 19th-century English School was very expensive. Now it seems overlooked, and if one seeks out quality and buys for love, then one may also find a very good investment — but that should never be the object of the exercise.

The Watercolours and Drawings Fair is at Covent Garden, London, until 5.30pm tomorrow; watercoloursfair.com