Tincture trail from Persia to Isatica

These two books could not be more timely. Vegetable dyes are in the news, as we become increasingly concerned with chemical pollution in the environment, and also seek a wider range of profitable crops for farmers to grow. Both are highly scholarly, wide-ranging studies of three plants that could perhaps find a new life in our changing world. The best chance of success at present lies with woad, which offers the same blue dye as indigo but in a weaker concentration, and is better suited to the European climate. Research has been under way for some years in the laboratories, and now in the fields, and commercial success is anticipated in producing blue ink for bubble-jet printers. Madder has long been prized for its natural red colour in the making of Turkish carpets, but it awaits further scientific development as a crop and needs to find additional uses.

The histories of indigo, woad and madder are told here by experts, who involve their readers in all the excitement and strenuous journeys of their research. They plunge us into prehistory, and then into a truly globalised world, which it is both sobering and awe-inspiring to contemplate. Jenny Balfour-Paul first encountered indigo in the Yemen and Middle East, and subsequently explored the dyer's art in Thailand, China, Japan, India and then in north and west Africa. Correspondents assisted her in Central and South America, but in Western Europe her searches coincided with a mounting interest in the past history of woad, manifest from 1987 at meetings in Erfurt in East Germany (a medieval stained glass window in Erfurt's church depicts woad dyers), and in France in 1995 in Toulouse. For longer still, English historians had nursed their distinctive story of woad, since the dye was still being grown for police and army uniforms in Lincolnshire in 1930. The county once had a settlement of woad workers near Boston, called Isatica, borrowing its name from the Latin word for woad, Isatis tinctoria L .

Robert Chenciner roams over different countries and writes in a different style, but he also carries his readers with him on an irregular route into the Caucasus, Turkey, and Persia and back to the Netherlands, Britain and France. Chenciner's study sprang out of an interest in carpets, notably those made in Dagestan in the Caucasus. The subject index in the Russian National Library in St Petersburg led him to a literature that poured forth between 1829 and 1860, when textile manufacture was expanding in Russia and the madder plant seemed to have a golden future in Dagestan. The best European experience was then gathered from the Netherlands, but every European country has its individual story, even Scotland where a surgeon in Dalkeith won an award for his home-grown madder in 1757. Chemists, who isolated the essential elements in the three plants, inaugurated their long, slow death as commercial products from 1869.

Both books combine practical wisdom with a tireless search for historical evidence in print, documents, textiles and photographs, and both deal with the use of the dyes in textiles, paints, and medicines, though their emphases differ. Both have abundant and varied illustrations, but Chenciner's are in black and white, whereas Balfour-Paul offers a magnificent selection in colour.

All three plants dictated severe conditions, and all were at some stage labour-intensive. But the labour supply could be remarkably different. Woad in the West Indies and southern states of America relied on slaves; in Germany, it was supplied by peasant farmers; in England, by labourers belonging to families with a long-standing tradition as "wadworkers". European historians have not yet appreciated or explored these contrasting solutions in different countries.

Madder posed yet other problems for it yielded no dye for two or three years, and other plants had to be grown between the rows. Drying the madder required ovens and a skill known best to the Dutch in Zealand. When ready for use, indigo was the most temperamental dye, and many superstitions enveloped it. The ramifications of dye-plants are endless, and these two books open up innumerably alluring pathways, not yet explored to their ends.

Joan Thirsk is emeritus reader in economic history, University of Oxford.