Artist’s Wife, 1439 by Jan van Eyck. Photograph: National Gallery/Groeningemuseum, Bruges

As a supporter and modest collector of portraiture, I have often wondered why it is that portrait painters have had to struggle for their place in the pantheon. Perhaps there is a feeling that portraiture lacks the universality of other forms, and is designed just to remind us of how people looked. The genesis of the portrait is often very personal – an artist is commissioned to do a portrait for the benefit of the subject, or of persons close to him or her. The artist who paints a landscape or still life is not addressing a closed circle of people; there is nothing private about such a painting. By contrast, there may be an assumption that the portrait of a named person is not addressed to us; we feel almost as if we are intruding.

Great portraiture, of course, transcends the personal. A portrait may be as powerful as any allegorical painting in what it says about life; about our vulnerability, our hopes and ambitions. When I look at a portrait, I am drawn first to the eyes, because it is there that one sees the essence of the subject. I then look for a detail in the clothing or the background which says something more general. This involves a very particular scrutiny, and it is one which I suspect comes from being a novelist.

Like many writers, I do not give detailed descriptions of my characters. I do, however, rely a great deal on descriptions of clothing or personal possessions. For example, in the No 1 Ladies’ Detective Agency books, I try to say a lot about Mma Ramotswe’s assistant, Mma Makutsi, through her possessions. We know that she has large glasses and problem skin – that is all that is said about how she looks. But we know, too, that she has a lace handkerchief of which she is very fond and which is becoming threadbare. This handkerchief stands for her desire to escape poverty and to make something of her life. A lot for a small hand-kerchief to do, but hopefully it works.

This moral function of portraiture – a reminder of our shared humanity – would by itself be sufficient reason for portraiture’s celebration. But there is so much more. In particular, the portrait lends itself to the portrayal of beauty. There are ugly portraits, of course, but these are not necessarily portraits of human ugliness. Domenico Ghirlandaio’s picture An Old Man and a Boy shows a man with a grossly bulbous nose looking down upon a perfect child. Both are beautiful, though; the man with his ugly nose and the child with his flaxen locks. And this, I think, applies to so many portraits. Even those who are not physically blessed may appear beautiful in a portrait. A good portrait painter will find beauty in any subject, because there is a sense, surely, in which the human face will always appear beautiful, caught in the right pose, seen in the right light, understood in the right way.

We are bombarded today with photographic images. This can make us forget that the face and body reflect the drama and possibilities of our lives, as well as reminding us of those feelings that make for a full, considered life. Painted portraiture provides a calm moment in which we can think about just these things. It helps us, I believe, to be more appreciative, more forgiving and ultimately kinder.

Alexander McCall Smith