Explore Our Collection: Virtual Mini-Exhibition - Looking at Dyes

  • Sample 1: Green
  • Sample 2: Pale Green
  • Sample 3: Pale Pink
  • Sample 4: Black
  • Sample 5: Yellow

This virtual mini-exhibition looks at the results of a dye analysis conducted in 1995 on one item in our collection, a Hexagon Mosaic Patchwork thought to date from the first half of the 19th century. Nine samples of different fabrics and colours were taken from this unfinished piece, where samples could be taken from the seam allowance on the reverse.

The first sample tested the green on the ground of this wavy striped patterned fabric. The results showed it was made by printing yellow, from Persian berries, over Prussian blue dye, to make a green. Prussian blue was an iron pigment dye found in fabrics in quilts between 1830 and 1860s. It gave a greenish blue, but wasn't fast to washing with soap. Persian berries were a widely used yellow mordant dye derived from buckthorn berries. Green was often made by printing yellow and blue, and was a difficult colour to achieve on it's own. It wasn't until 1895 that Alizarin, a synthetic green, could achieve the colour in just one process.

The second sample examined the pale green ground on this leaf print. Although the evidence was circumstantial rather than confirmed through testing, it was concluded that it was made with Scheele's Green, or Copper Arsenite. Although this was an easy pigment to use, and was the only way to achieve a green (though pale) through one process, it was also highly toxic. Invented by pharmaceutical chemist Carl Wilhelm Scheele in 1775, it was used in a variety of products including wall paper, food stuffs, paint and even children's toys well into the 19th century.

If you ever manage to time travel, just make sure you don't eat the green sweets in the attractive green wall-papered Victorian parlour....

The next sample looked at the pale pink in the centre of this hexagon rosette. Pink can be achieve by using madder with an alum mordant, but this particular pale shade was made using Cochineal, a dye derived from the crushed bodies of female scale insects. Cochineal is an unusual choice for the cellulosic fibres of cotton as it's colour isn't as strong as it is on wool and silk (where is produces a vibrant red), and also isn't a fast dye on cotton. It is particularly found in the 1820s-50s but not after that date.

The black zones were of particular interest in this fabric. Black was often created in the madder style, using a strong iron mordant. If madder wasn't used, the next choice was often bark dye logwood. After 1860, blacks based on aniline appeared. However this black has been achieved by printing cochineal over Prussian Blue, a result that surprised dyes expert and Guild expert Deryn O'Connor and the textile research associates conducting the tests.

This vibrant yellow colour was achieved using Persian berries. Yellows were often achieved using dyes derived from plants or barks which were used with mordants such as alum, iron or chrome, each one giving a different colour. Alum gave a clear yellow, whilst iron gave an olive shade and chrome an orange/yellow. Yellow is often fugitive and does not always survive well.