Dyestuffs and dyeing in general.—The beautiful illumination of the Book of Kells, the Book of Mac Durnan, and numerous other old manuscripts, proves that the ancient Irish were very skilful in colours: and it will be shown here that the art of dyeing was well understood. The dyestuffs were not imported: they were all produced at home; and were considered of great importance.
The people understood how to produce various shades by the mixture of different colours, and were acquainted with the use of mordants for fixing them. One of these mordants, alum, is a native product, and was probably known in very early times. Dyeing was what we now call a cottage industry, i.e. the work was always carried on in the house: as I saw it carried on in the homes of Munster more than half a century ago. In the cultivation of the dye-plant, men might take a part: but the rest of the process was considered the special work of women, so that men seldom assisted. Even the presence of men or boys looking on at the work was considered unlucky. Cloth was dyed in the piece, the wool being left of the natural colour till after weaving and fulling. But woollen cloth was often worn without being dyed at all—just with the shade it brought from the back of the sheep.
Ground Colour.—There were two main stages in the process of dyeing. The first was imparting a ground or foundation colour of reddish brown, which was done by steeping and boiling the cloth with the twigs of the ruam or alder. This was what the people called riming, from "ruam." After this the cloth was ready for the second stage—imparting the final colour: which was done by boiling it with the special dyestuff.
Black.—The dyestuff for black was a sediment or deposit of an intense black found at the bottom of pools in bogs. It always contained more or less iron, which helped in the dyeing. Boiled with this, the cloth acquired a dull black colour: but if some twigs or chips of oak were added, the colour produced was a glossy jet black, very fixed and permanent.
Crimson.—A crimson or bright-red colour was imparted by a plant anciently called rud or roid, which required good land, and was cultivated in beds like table-vegetables, requiring great care. There were several stages of preparation; but the final dyestuff was a sort of meal or coarse flour of a reddish colour.
Blue.—To dye the cloth blue, after it had been rimed, it was boiled with a dyestuff obtained from woad, called in Irish glaisin [glasheen]. This name was also given to the prepared dyestuff, which was in lumps or cakes. As in the case of roid, there were several stages in the preparation of the final dyestuff.
Purple was called in Irish corcur. In one of the pages of an ancient manuscript now in Turin, is a passage written by an Irish hand in the beginning of the ninth century, which proves that at that early time the Irish were acquainted with the art of dyeing purple by means of a lichen. The knowledge of dyeing from rock lichen was never lost, but was continued from generation to generation down to recent times; and early in the last century considerable quantities of the lichen dyestuff in the form of balls were sold in the markets of Dingle in Kerry.
The ancient Irish obtained a beautiful purple from small shellfish like cockles; and in some places whole heaps of shells have recently been found, all broken uniformly at one particular point—just the point inside which was situated the elongated little sac containing the purple colouring matter: evidently with the object of extracting the precious little globule. This method of obtaining purple dye continued to be practised in the eastern Irish counties, as well as on the opposite coast of Wales, down to the beginning of the last century. The art continued in Wales, as well as in Ireland, from the earliest times: for the Venerable Bede records that in his day (the eighth century) the Britons (or Welsh) produced a most beautiful purple colour from shellfish. The celebrated Tyrian purple was produced in a similar way.
The purple dyestuff, however obtained, was produced in very small quantities, so that it was extremely scarce; and the colour was excessively expensive in Ireland as elsewhere: on the Continent in old times it was worth thirty or forty times its weight in gold. Partly for this reason, and partly for its beauty, purple was a favourite with kings and great chiefs, so that writers often designate it a royal or imperial colour.
Saffron.—Until recent times linen was dyed saffron with the cróch or saffron plant (Lat. crocus), which was the simplest of all the dyeing operations.
Popular Knowledge of Dyeing.—The Irish peasantry of the present day, as well as the Highland Scotch, possess considerable knowledge of the stuffs—chiefly obtained from herbs—used in imparting various colours, and are skilled in simple dyeing: knowledge and skill that have descended to them from old times.