
The chemical structure of '6,6′-dibromoindigo', the main component of 'Tyrian Purple'
'Tyrian purple' (
Greek: '', porphyra''), also known as ''royal purple'' or ''imperial purple'', is a 'purple-red'
dye made by the ancient
Canaanites/
Phoenicians in the city of
Tyre, from a mucus-secretion of the hypobranchial gland of a marine
snail known as ''
Murex brandaris'' or the Spiny dye-murex.
The Phoenicians also made a 'purple-blue'
indigo dye, called ''royal blue'' or ''hyacinth purple'', which was made from a related species of marine snail, called ''
Murex trunculus'' or the Banded dye-murex.
Tyrian purple was expensive: the fourth-century BC historian
Theopompus reported, "Purple for dyes fetched its weight in silver at
Colophon" in Asia Minor.
[1]
Overview

6,6'-dibromoindigo, the major component of Tyrian purple
The fast, non-fading dye was an item of luxury trade, prized by
Romans, who used it to colour ceremonial robes. It is believed that the intensity of the purple hue improved, rather than faded, as the dyed cloth aged.
Pliny the Elder described the dyeing process of two purples in his ''
Natural History''
[2]:
The ancient method for mass-producing the two murex dyes has not yet been successfully reconstructed, but this special "blackish clotted blood" colour, which was prized above all others, is believed to be achieved by double-dipping the cloth, once in the indigo dye of ''H. trunculus'' and once in the purple-red dye of ''M. brandaris''.
The Roman mythographer
Julius Pollux, writing in the second century BC, asserted (''Onomasticon'' I, 45–49) that the purple dye was first discovered by
Heracles, or rather, by his dog, whose mouth was stained purple from chewing on snails along the coast of the
Levant. Recently, the archaeological discovery of substantial numbers of Murex shells on
Crete suggests that the
Minoans may have pioneered the extraction of Imperial purple centuries before the Tyrians. Dating from colocated pottery suggests the dye may have been produced during the Middle Minoan period in the 20th–18th century BC.
[3][4]
The main chemical constituent of the Tyrian dye was discovered by
Paul Friedländer in
1909 to be '6,6′-dibromoindigo', a substance that had previously been synthesized in
1903. However, it has never been synthesized commercially.
[5][6]
Modern output
Tyrian purple
The true colour of Tyrian purple, like most high chroma
pigments, cannot be accurately displayed on a computer display, nor are ancient reports entirely consistent, but these swatches give an indication of the likely range in which it appeared:
_________
_________
This is the
sRGB colour #990024, intended for viewing on an output device with a
gamma of 2.2. It is a representation of
RHS colour code 66A
[7], which has been equated to "Tyrian red"
[8], a term which is often used as a synonym for Tyrian purple.
Shades of Tyrian purple colour comparison chart
Modern research shows, as discussed above, that various formulations of Tyrian purple existed on a continuous spectrum within approximately the following range of
colours:
- Bright Tyrian Purple (Bright Imperial Purple) (Tyrian Pink) (Hex: #B80049) (RGB: 184, 0, 73)
- Medium Tyrian Purple (Medium Imperial Purple) (Tyrian Red) (Hex: #990024) (RGB: 97, 64, 81)
- Tyrian Purple (Imperial Purple) (Hex: #66023C) (RGB: 102, 2, 60)
References
1. Theopompus, cited by Athenaeus (12:526) around 200 BC; according to Gulick, Charles Barton 1941. ''Athenaeus, The Deipnosophists.'' Cambridge: Harvard University Press.
2. Pliny the Elder, ''The Natural History'' (eds. John Bostock, H.T. Riley) Book IX. ''The Natural History of Fishes''. Chapters 60-65. [1]
3. Reese, David S. (1987). "Palaikastro Shells and Bronze Age Purple-Dye Production in the Mediterranean Basin," Annual of the British School of Archaeology at Athens, 82, 201-6).
4. Stieglitz, Robert R. (1994), "The Minoan Origin of Tyrian Purple," Biblical Archaeologist, 57, 46-54.
5. 'Indigo', 'Encyclopædia Britannica' ISBN 0-85229-378-X
6. Tyrian purple: 6,6’-Dibromoindigo and Related Compounds, Cooksey C. J., , , Molecules, 2001
7. "RHS, UCL and RGB Colors, gamma = 1.4, fan 2", ''Azalea Society of America website'' [2] (this gives the RGB value #b80049, which has been converted to #990024 for the sRGB gamma of 2.2)
8. Buck, G. ''Buck Rose Website'', Page 5 [3]
See also
★
Indigo dye
★
Purple
★
Hexaplex trunculus
External links
★
Silver, M. ''Ancient Economies I (continued), Topic V: The Argonaut Epos and Bronze Age Economic History'', Economics Department, City College of New York