In Parshas Teruma it mentions Argaman. The way it was translated in Yeshiva was purple. Is Argaman really purple? Shir Hashirim 7:6 says V'Dallas Roshech Ka'Argaman. Rashi, Rashbam, Even Ezra, Metzudas Davis, Malbim all translate this to mean the color of the hair is like Argaman. I have never seen non dyed purple hair! So what color is Argaman? (Sources please)
My understanding has always been that argaman refers to Tyrian Purple, or at least a similar reddish-purplish dye, produced from murex shells. The archaeologist Zvi Koren has written about this and has found a fabric at Qumran of murex-dyed wool that he interprets as having been Tyrian purple.
With regards to the hair: some scholars have suggested (and I agree with them) that the reference to argaman-coloured hair in SoS 7:6 refers to the purplish sheen that black hair takes when it has been dyed with henna (see, for example, here, here, or here).
Taken from R Aryeh Kaplan's translation of the Torah
dark red (Ibn Ezra; Ibn Janach; Pesikta Rabathai 20:3, 86a). Argaman in Hebrew. Others state that it is similar to lake, a purplish red dye extracted from lac (Radak, Sherashim; Rambam on Kelayim 9:1; cf.Yad, Kley HaMikdash 8:13). Although the Septuagint translates argaman as porphura or porphoreus, which means purple, in ancient times, 'purple' denoted a deep crimson, most notably the dye obtained from the purpura snail. Ancient sources indicate that it was close to the color of fresh blood (Iliad 4:141). Talmudic sources state that argaman was obtained from a living creature (Yerushalmi, Kelayim 9:1), and other sources indicate that it was an aquatic creature (I Maccabees 4:23; Abarbanel on Exodus 25:10). Like tekheleth it was obtained from Tyre (2 Chronicles 2:6, cf. Ezekiel 27:16) as well as Greece or Italy (Ezekiel 27:7, Targum ad loc.).
This dye was therefore most probably derived from a species of the murex or purpura snail. The Septuagint translation, porphura, also denotes the purpura snail. Ancient sources indicate that snails caught in the north yielded a blue dye, while those from the south yielded a reddish dye (Aristotle, History of Animals 5:15). Argaman was most probably obtained from the 'red purpura,' Purpura haemastoma, known to the ancients as the buccinum (Pliny 9:61; see Reshith Limudim 1:6).
In ancient times, material dyed with this color was extremely valuable (cf. Shabbath 90a; Kelim 27:12), and it was weighed as carefully as gold (Kelim 29:4).
The Hebrew word argaman is obscure, but it is thought to be related to ragman, Sanskrit for red. Others say that it is related to the root arag, meaning 'to weave' (BeMidbar Rabbah 4:17, 12:4). Some therefore say that it consisted of two types of thread or three colors woven together (Raavad, Kley HaMikdash 8:13). Some say that it is an irridescent dye, having greenish overtones (Zohar 2:139a; Tikkuney Zohar 70, 127b, top, 124a, top; Maaseh Choshev 3:2).
The Greek term for Argaman seems to be porphyra, and this color was used to describe a variety of shades. see http://community.middlebury.edu/~harris/Classics/purple.html. (Note his comment on comparing the color to the sea, "eino ke'ein hayam") Argaman was probably used in the same way, referring as much to a hue or iridescence as to a specific color.
I've learned that it is crimson red. While some people have quite reddish hair, I do not think natural crimson hair exists.
The Rambam in Hilchos Kli Mikdash 8:13 writes that it was red,the Raavad said it was two or three dyes mixed together .
וכל מקום שנאמר בתורה שש או בד הוא הפשתים והוא הבוץ. ותכלת האמורה בכל מקום היא הצמר הצבוע כעצם שמים שהוא פתוך מן הכוחל. הארגמן הוא הצמר. הצבוע אדום. ותולעת השני הוא הצמר הצבוע בתולעת:
השגות הראבד הארגמן הוא הצמר. א"א לי נראה ארגמן ארוג משני מינין או משלשה צבעין על כן נקרא ארגמן: