The Great Tekhelet Debate -- Blue or Purple?

by Baruch and Judy Taubes Sterman

For ancient Israelites, TEKHELET was God's chosen color. It was the color of the sumptuous drapes adorning Solomon's Temple (2 Chronicles 3:14) as well as the robes worn by Israel's high priests (Exodus 28:31). Even ordinary Israelites were commanded to tie one string of tekhelet to the corner fringes (Hebrew, tzitzit) of their garments as a constant reminder of their special relationship with God (Numbers 15:38-39).

But how do we know what color the Biblical writers had in mind? While tekhelet-colored fabrics and clothes were widely worn and traded throughout the ancient Mediterranean world, by the Roman period, donning tekhelet and similar colors was the exclusive privilege of the emperor. And so it happened that sometime around the seventh century C.E., probably hastened by the Islamic conquest of the Levant, the source and identity of tekhelet, and knowledge of its manufacture, slipped into obscurity.

About a century ago, as part of his doctoral research on "Hebrew Porphyrology" (the study of purple), Isaac Herzog, who years later became the first chief rabbi of Israel, corresponded with the greatest dye chemist of his day, Paul Friedlander, about possible sources for Biblical tekhelet. Archaeological evidence and an exhaustive survey of the writings of rabbinic scholars and Greek and Roman naturalists had convinced Herzog that tekhelet was a bright sky-blue obtained from the natural secretions of a certain sea snail, the Murex trunculus, known to produce a dark purple dye. [1]

But the esteemed chemist challenged Herzog's contention: "I consider it impossible to produce a pure blue from the purple snails that are known to me," Friedlander said emphatically. [2]

Unfortunately, neither Herzog nor Friedlander lived to see a 1985 experiment by Otto Elsner, a chemist with the Shenkar College of Fibers in Israel, proving that sky-blue could, in fact, be produced from murex dye. During a specific stage in the dyeing process, exposure to ultraviolet rays (such as those found in sunlight) can cause the molecules that give the dye its natural purple color to transform into pure indigo, thus leaving the dye an unadulterated sky-blue.

The tied strings (tzitzit) of this traditional Jewish prayer shawl have been dyed a shade of blue that many identify with Biblical tekhelet.

Yet the debate surrounding the exact color of tekhelet was not settled. Depending on how long the murex dye is exposed to light and at what stage in the dyeing process, a wide range of colors and shades can result. In addition, some chemists claim that ancient dyers, who created their dyes primarily using bacterial fermentation in covered vats, probably did not know how to adjust colors through exposure to sunlight, so that their dyes would have tended to be a much darker purple. In view of the obvious expertise of ancient dyers, however, this does not seem a convincing supposition.

Furthermore, there is some literary and archaeological evidence that tekhelet may have been more purple than blue. Writing in the 11th century, the great Biblical exegete Rashi defined tekhelet as a deep blue or dark violet, "the color of the sky as it darkens towards evening" (commentary on Numbers 15:38). And at the Herodian fortress of Masada, a small swatch of first-century, violet-colored wool was discovered during Yigael Yadin's 1960s excavations. A recent analysis of the violet-colored wool by Zvi Koren, an archaeochemist at Shenkar College, found that its violet hue was produced with murex dye.

But Rabbi Herzog, like the overwhelming majority of Jewish scholars since antiquity, had firmly believed that tekhelet was sky-blue, with no purple tinges. Maimonides (1135-1204) had declared unequivocally that tekhelet was "the color of the sky opposite the sun when there is a clear sky" (Mishneh Torah, Laws of Tzitzit 2:1). Nearly a thousand years earlier, the second-century scholar Rabbi Meir declared, "Tekhelet resembles the sea, and the sea resembles the heavens, and the heavens resemble God's holy throne" (Midrash Sifre, Shelach).

One major piece of evidence in favor of designating tekhelet as sky-blue involves an infamous story of forgery related in the Babylonian Talmud (Baba Metzia 61b).  Unscrupulous merchants were substituting a fraudulent, cheaper dye called kala ilan in place of authentic tekhelet. The impostor, a plant-derived indigo, was a dead ringer for the real stuff, and the Talmud claims that only God could tell the difference. If tekhelet looked exactly like kala ilan, it must have been the same color as indigo: sky-blue.

Wayne Horowitz, an Assyriologist at the Hebrew University of Jerusalem, offers further significant linguistic evidence supporting the sky-blue option. In ancient Mesopotamia, there was no word for the color blue in either Sumerian or Akkadian. Hence, Sumerian uqnu, the word for the precious blue gem lapis lazuli, was adopted to mean lapis lazuli-colored, i.e., blue and all its various shades. This term was apparently applied to the sky, and later to blue wool (uqndtu). When the foreign word takiltu (Hebrew, tekhelet) was adopted into Akkadian, it was rendered with the same cuneiform signs as uqnatu. This suggests that to Mesopotamian eyes, the colors of lapis lazuli, the sky and tekhelet were equivalent.

So what color was ancient tekhelet? For us, the founders of the Ptil Tekhelet Foundation, this is no mere academic question. We believe the preponderance of evidence -- archaeological, linguistic and literary -- clearly supports the traditional position and points to sky-blue as the authentic color of tekhelet. Over the past 25 years, we have produced hundreds of thousands of murex-dyed tzitzit strings that hang from prayer shawls around the world, reminding those who wear them of the sea, the sky and God's holy throne.

End Notes:

[1] See Ari Greenspan, "The Search for Biblical Blue," Bible Review, February 2003.

[2] Isaac Herzog and Ehud Spanier, The Royal Purple and the Biblical Blue -- Argaman and Tekhelet: The Study of Chief Rabbi Dr. Isaac Herzog on the Dye Industries in Ancient Israel and Recent Scientific Contributions (Jerusalem: Keter,1987), p. 116.

Baruch and Judy Taubes Sterman are authors of The Rarest Blue: The Remarkable Story of an Ancient Color Lost to History and Rediscovered (Guilford, CT: Lyons Press, 2012).

Hope of Israel Ministries -- Preparing the Way for the Return of YEHOVAH God and His Messiah!

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