Catherine Yass’s photographic lightboxes are straightforwardly beautiful - we do not have to don our thinking caps to appreciate them. It is perhaps because of her training at the Slade School of Art that she takes such a painterly delight in colour. This does not mean that her work is any less thoughtful than that of the other Turner Prize contestants, Fiona Banner, Liam Gillick and Keith Turner, but it maybe explain her high ranking with the William Hill betting shop as a likely prizewinner.

Yass photographs people and places, but transforms often mundane subject matter - such as toilets or hospital corridors - by her colour, in particular, a vivid shade of ultramarine blue. Her heightened hues first came into being by mistake when she was at art school and an incorrectly loaded film was processed as a negative. Yass was impressed by the colours the mistake produced and went on to create works in which two images, shot with an interval of a few moments between them, were superimposed. In the printing of the resulting images, Yass makes further adjustments to the tones she uses and, where there is strong light or transparent areas within an interior, they turn into what has been described in a catalogue of her work (Catherine Yass, Asprey Jacques, pound;20) as “Catherine’s blue”. These transparent spaces also develop as a result of the sitters moving during the time between one exposure and the next. The progression of time within parallel moments implicit in the process is important to the artist.

Students who experiment with photography will know how much an image can be manipulated by means of the production process. Yass exploits the possibilities to the full. In the same catalogue she writes about the video loops she made in Tokyo and Walsall, saying: “In my Tokyo videos I’ve taken the constituent colours of the video, red, green and blue and I’ve slid them apart; during the video they slide apart and come back together again. The image fragments and reassembles.” Her words make clear the element of skill involved in her photography - filming is only the start of the artwork.

Yass has an eye for the unusual within the everyday. She picks out an angle of a hospital corridor, urinals in a station and a park, or a set of glass bricks in a graffiti stained prison cell, and makes us focus intensely on something we would normally barely notice or perhaps avoid looking at. She says that with photography she “wanted to enable one to see objects in unfamiliar ways” (Catherine Yass, Asprey Jacques). The contrast between the plainness or even ugliness of the subject and the beauty of its colours creates a special quality, often extremely beautiful, sometimes spooky and sometimes disturbingly hallucinogenic.

Of all the artists exhibiting in the Turner Prize, Yass’s work relates most closely to current classroom practice in its experimentation with colour and light. She is, of course, not alone in her study of the expressive potential of blue, which has fascinated many other creative artists, not only painters like Edvard Munch, Pablo Picasso and Yves Klein, but composers such as George Gershwin, whose works include Rhapsody in Blue, and poet Stephane Mallarme, for whom the concept of “l’azur” represented an unattainable ideal. She shares her interest in the anonymity of hospital corridors with Gary Hume, an artist shortlisted in the 1996 Turner Prize. The surface appearance of both of their work is seductive, but the seduction is employed by them to heighten the underlying bleakness.

In her Turner Prize display Yass will show three new lightbox works that relate to her film Descent 2002, in which she lowered a camera from a crane down the entire height of a tower block under construction at Canary Wharf. Yass explained: “I loved the idea of shooting something from a temporary viewpoint that didn’t really exist and wanted it to be about the dreamlike seduction of falling”.

She was helped to realise the unusual atmosphere she wanted by the day’s misty conditions, which shrouded neighbouring buildings, blurring their forms and softening their colours. Curator Lizzie Carey-Thomas describes the “giddying sense of free-fall” in the still images shot from the top of the crane with the camera facing downwards, and the effect of the high viewpoint on the buildings down below, which “are fractured and blurred, at times reduced to coloured streamer-like ribbons, fluctuating between abstraction and representation”.

Miquette Roberts is education resources officer at Tate Britain The Turner Prize 2002 exhibition at Tate Britain runs until January 5, 2003. The winner will be announced on December 8, 2002 www.tate.org.ukbritainexhibitionsturnerprize

CATHERINE YASS 1963-

Catherine Yass was born in London. After graduating from the Slade School of Art in 1986, she completed an MA at Goldsmiths’ College of Art, London, in 1990. She was commissioned to create a video for the opening of the new gallery at Walsall.

SUGGESTIONS FOR SECONDARY TEACHERS

Subject matter

* Without having to be coaxed up to the top of a crane, your students can experience some of Yass’s giddying free-fall effects by, for example, holding a camera and directing it downwards from the top of a flight of stairs.

In school or at home they can search for a special place which tends to pass unnoticed in everyday life. What are its colours? What is its mood?

Technique

To transform the appearance of their special place they can either use paint or photography. Painting will allow them more choice of colour. Ask them to think about the colours they would choose to transform the atmosphere of the place. Can they beat blue’s domination in art as a mood-creating colour?

If students choose photography as their medium they should buy a roll of EPP (Kodak 100) transparencyslide film to take their photographs. These films could be processed either in the school developing room or at a photo lab, with specific instructions for the film to be cross-processed. Strange colour distortions will result.

This year’s Turner Prize is not suitable for primary children, but their teachers could be inspired by seeing Yass’s work. They could buy sheets of coloured acrylic to place over the childrens’ paintings, thus transforming the colours, and discuss the effects created with them. They could view any particularly dismal areas in the school building through the lens of a coloured acrylic sheet and discuss which new colour has the most uplifting effect.