Self-Portrait, caught mid-stroke

You are baptised in Haarlem on 28 July 1609. Your father, Jan Willemsz, owns a brewery called the Leyster, the lodestar, and the family takes its name from it.

Who taught you is not recorded. Samuel Ampzing's book in praise of Haarlem, published in 1628 and written before February 1627, mentions you beside the workshop of Frans Pietersz de Grebber, whose daughter Maria also painted, but his wording leaves it unclear whether you trained there. No document says you studied with Frans Hals, though your work comes closer to his than almost anyone's.

Ampzing's own question shows how rare you are: "Who ever saw a painting made by the hand of a daughter?" Your family moves to Vreeland near Utrecht and, by September 1629, to Zaandam; you are back in Haarlem by November 1631, a witness at the baptism of one of Hals's children.

From 1629 you sign and date your pictures, with a monogram of your own: the letters J and L joined, with a star beside them, a play on your name. This self-portrait carries no signature.

By 1633 you are a master in Haarlem's Guild of St Luke, one of very few women ever admitted; the NGA calls you the first for whom a body of work can be named. In 1635 you have three pupils. One of them, Willem Woutersz, leaves for Frans Hals's studio, and in October you go before the guild and win payment from his mother.

In 1648 the Haarlem historian Theodorus Schrevelius, listing women who could compete with men in painting, singles you out as the true "leading star" in art, the same pun on your name.

A self-portrait at the easel is an old type. Painters show themselves dressed well, at work, to claim that painting is a liberal art and not a craft; Catharina van Hemessen did it in 1548. You keep to that tradition and break it at once.

Dress for the claim

A starched collar edged with lace, a fine cap, silk sleeves: formal clothes, the NGA notes, inappropriate for anyone busy painting. They say what you can afford, and what painting is worth.

Turn and speak

Your arm over the back of the chair, your lips parted, you turn to us as if interrupted. That momentary air belongs to Frans Hals's portraits of the 1620s; such active poses were rare in portraits of women.

Show what you sell

On the easel, not your own face but a laughing fiddler from one of your merry company scenes: the kind of picture a buyer could order from you.

Bow and brush

His bow and your brush lie almost parallel. Wheelock reads it as a claim: as he has mastered his instrument, you have mastered yours.

When is this? The NGA dates it about 1630, from the collar's style, the cap (close to one in your Carousing Couple of 1630) and the violinist's source. Frima Fox Hofrichter proposed instead that you painted it in 1633 as your masterpiece for the guild, which required a painting "two feet large" of new masters; Wheelock thinks that probably not correct.

The canvas is a plain weave with many slubs and irregular threads. Over it goes a smooth, thin white ground, and over that a grey-brown imprimatura, a thin coloured wash that will show through in the half-tones and give the whole picture its key.

The X-radiographs show cusping, the wavy distortion of the weave where it was pulled onto a frame, along all the edges except at the lower left. So the picture is about the size you made it, though the tacking margins were trimmed when it was lined.

Ella Hendriks and Karin Groen examined six of your signed paintings for the 1993 exhibition. As a review summarised them, your canvases had an oil imprimatura over a flesh-coloured chalk ground, the usual Haarlem practice. The NGA describes this ground as white; this guide follows the NGA for this painting.

What pigments you used here is not known: no analysis of this painting has been published. The swatches in the diagram are colours seen, not colours found.

Infrared photography and infrared reflectography, which see through some paint to darker layers beneath, show that the picture on your easel first held something else: a woman's head, with parted lips, turned slightly to the left. The NGA's conservators call it a major change. It is now partly visible to the naked eye, as a pentimento.

Whose head? Wheelock thinks it was probably you, a self-portrait within the self-portrait, as the tradition of the painter at the easel would lead one to expect. Why change it? Perhaps because the merry company with the fiddler had sold well, or, as Hofrichter suggested, to show that you could paint both portraits and lively scenes from life. No document says.

The fiddler comes from your Merry Company of about 1629 to 1631: the same blue beret, the same open laugh, the same bow raised across the strings. On the easel you leave him unfinished. Today he is the most worn part of the painting.

The easel today.

The same, contrast stretched: a darker head-shaped form left of his face.

Both are cut from the NGA's open-access photograph; the right one is only that photograph in grey with its contrast stretched, not an infrared image. The NGA's reflectogram, which shows the head clearly, is in its online catalogue.

After your death your name fades, and dealers and scholars give your pictures to Hals. This one carries no monogram to argue with them. It was attributed to you in 1926, then given to Hals by many scholars through the 1930s, shown at the Hals exhibition in Haarlem in 1937, and is now accepted as yours by the NGA and by scholars generally.

The canvas has had a hard life. A long horizontal rectangle of it is missing at the lower left, in the red skirt, and has been replaced by an insert of fine, tightly woven canvas with none of your paint or ground; the red there is a restorer's. The paint is pitted all over with tiny holes of the kind made by too much heat during lining, abraded and flattened, with small losses at the top and in your left cheek.

In 1992 the NGA removed the discoloured varnishes that, in Wheelock's words, had severely disfigured the painting, and the old retouching. Since then the picture has become, as he puts it, iconic.