1) It appears from Tosfos that it is a sky-blue color. The Metargem, printed at the back of the Gemara, writes that in fact it should read "Itzanda." He writes that according to most of the ancient authorities this is the "Techeles" color, which we know is the same color as the sky.

2) Tosfos in Chulin (47b, DH Ela) translates this color as "Indish," but it appears that this is the same as Itzanda.

3) Ma'amar Pesil Techeles, by the famous Rebbe of Radzin (who claimed he knew how to derive the Techeles color) writes on page 29 that the basis of Techeles is the Iranda color, into which small flashes of green are mixed.

Kol Tuv,

Dovid Bloom

2) (a) Here is an argument whereby one can claim that Techeles is dark blue. Rashi in Chumash Bamidbar (end of Parshas Shelach) writes that Techeles is similar to the color of the sky which blackens towards evening time. Rashi in Chumash seems to be consistent with what he writes in Sotah 17a, where the Gemara says that Techeles is similar to the sea, and the sea is similar to the sky. Rashi (DH sheha'Techeles) writes that Techeles is not really so similar to the sky but it is "similar to similar." In other words, it is a twice-removed "similar." Rashi in Sotah seems to be referring to the sky in the middle of the day, and thus Techeles is not really so similar to this, but only "similar to similar" (see also Ritva to Chulin 89a, DH Mah).

At any rate, it clearly appears from Rashi in Chumash that Teceheles is a dark blue, since he writes that it is the color of the sky when the sky is turning blacker towards evening.

(b) However, I wish to strengthen my argument that according to Tosfos in Sukah, Techeles is more similar to the blue of the sky in the middle of the day. I contend that Tosfos does not learn like Rashi on the "similar to similar" idea. My proof is as follows. Tosfos in Sukah writes that Techeles and Karti are "Me'at Meshunin Zeh mi'Zeh." This means that they are only slightly different from each other. Tosfos then writes that Techeles is similar to the sea, and the sea is similar to the sky. We see that Tosfos is trying to indicate what the color of Techeles is, and he does this by showing that it is similar to the sea and the sky. This suggests that Tosfos is showing that Techeles really is similar to the sky. If Tosfos would have held like Rashi, it would not have helped him to cite the "similar to similar" Gemara, because according to Rashi this Gemara suggests that, on the contrary, they are not so similar, since otherwise the Gemara would not have expressed it in this "twice-removed similar" fashion.

If we are correct in arguing that Tosfos and Rashi are not of the same opinion, we can assert that according to Tosfos, Techeles is a lighter blue.

(c) Of course, much research has been done on this subject. Many have labored to determine the identity of the Chilazon and what color is Techeles. See Sefer Ha'Techeles, by Menachem Borstein (published 5748). Since the publishing of this book, there has been much further research, including work published in Lakewood.

Kol Tuv,

Dovid Bloom

1) It seems that certainly one may not mix water with the Techeles. The source for this is the Gemara in Menachos 42b, which tells us that one makes the Techeles color by taking blood of the Chilazon together with "Samanin" (dyes), throwing them into a kettle, and boiling them. Tosfos (DH v'Samamanim) writes that he is perplexed how one is allowed to mix in anything together with the Techeles. Tosfos answers that possibly the material may be classified as Techeles only if it is mixed together with Samamanim. The Noda b'Yehudah (Orach Chayim 1:1, DH v'Achshav) explains that since the Chilazon blood does not hold so well when dyed into the wool unless Samamanim are mixed in, this means that the Samamanim are an integral part of the Techeles color. The Noda b'Yehuda also cites the Rambam (Hilchos Tzitzis 2:2) who says that Samamanim are mixed in the way that dyers usually do. Since the normal way of making color is to mix in Samamanim, we can assume that the Torah also wants us to use dyes together with the Chilazon blood.

We learn from all of this that the only reason why one is allowed to mix dyes together with the Chilazon blood is that otherwise the color will not hold fast. If not for this reason, the opinion of Tosfos would be that it is impossible to mix other substances with the Chilazon blood. It follows that certainly one may not add water, especially if one's motivation for doing this is merely to save money by usng less Chilazon.

2) (a) The Mishnah that you cited is in Berachos 9b. However, the Gemara there asks immediately, what does the Mishnah mean when it says "between Techeles and white"? It cannot mean between a lump of white wool and a lump of Techeles wool, because in the middle of the night one could also distinguish between them! The Gemara answers (according to Rashi) that the Mishnah is referring to a piece of clothing where the Techeles color has not held fast in some parts. The Mishnah refers to the moment in the end of the night when there is enough light to distinguish between the Techeles part and the white part of the same item of clothing. According to Tosfos, the Mishnah refers to when it is bright enough to distinguish between the Techeles strings and the white strings of the Tzitzis. Since the discernement involved is slightly more delicate, one can imagine that it is possible that the shade of Techeles might be somewhat darker.

(b) However, I think your observation from the Mishnah in Berachos 9b is a very important one, Martin. Even the commentaries who maintain that the Techeles color is quite dark cannot go too far on this, because you have proven that it must have some similarity to white. In fact, I saw that the Radziner Rebbe (who claimed he had rediscovered the Techeles) cites in his Sefer, "Sefunei Temunei Chol" (chapter 3, page 30), the opinion of Rashi on Chumash at the end of Parshas Shelach (that I cited in my second reply above), that Techeles is similar to the blackening sky towards evening time. However, the Radziner Rebbe writes that according to this, "the color of Techeles must tend towards blackness and have blackness mixed in with it a little." We observe that even according to Rashi's opinion there is only a limited similarity to black.

Hatzlachah Rabah,

Dovid Bloom

Techeles is not similar enough to the firmanent that one could give a Halachic definition of Techeles according to the color of the latter. However, it does bear a resemblance to the firmanent, and it is sufficiently close that when one sees Techeles one is reminded of the firmanent.

So Techeles is not scientifically close to the color of the Raki'a, but there is enough of a connection for the ethical association to be aroused when one sees Techeles.

Kol Tuv,

Dovid Bloom

This is fascinating!

However the color of the blue hyacinth plant can be mid-blue and the hyacinth bulb is light purple or cream in color, so techeles is not necessarily dark blue according to Tosfos.

It should be added that the translation of techeles as hyacinth is by no means new. I believe that in the Greek translations of the Chumash (in the time of the second Beis Hamikdash) it was translated as hyacinth (Chief Rabbi Herzog wrote at length about this). However I suspect that it may be quite a new claim that Tosfos also learns this way. Tosfos actually writes Iranda, but HaMetargem (which was written at the time of the publication of the Vilna Shas around 130 years ago) changes this to Itzanda, and one can understand how this is equated with Hyazinthe in German and hyacinth in English.

Yasher Koach

Dovid Bloom

I have found more, very early sources that there is a connection between Techeles and hyacinth.

1) With Purim not far away, the following source is timely. The Book of Esther 1:6 describes the decorations at the feast of Achashverosh. One of the colors displayed was Techeles. The Midrash (Esther Rabah 2:7) states that Rav Bibi said that Aquilas translated this into Greek as "Teynun." The Chidushei Radal #8 cites the Aruch (written by a major Rishon, Rabeinu Nasan of Rome, who was a contemporary of Rashi), in the entry "Teynun," who writes that the Greek origin of this word is "Yakintinun." One can understand that "Yakintinun" is equivalent to "hyacinth." The Aruch writes that Yakintinun is the color of Techeles and suggests two possibilties for how "Yakintinun" became "Teynun": either there was a scribal error and part of the word Yakintinun was omitted, or "Teynun" is a shortening by Chazal of the word "Yakintinun." (It should be noted that in the edtions of the Aruch with English words, the word hyacinth is mentioned explicitly here.)

2) If we look at the entry "Yakintin" in the Aruch, we find that he cites another source from Chazal for hyacinth. This is from Midrash Rabah Bereshis 79:7 which describes the 100 "Kesitah" with which Yakov Avinu bought the field. The Midrash states that this includes "Deyaknita" which are placed in bracelets. The Aruch writes that the correct text in the Midrash is "Yachkenita," which again is a hyacinth-color jewel, and is the color of Techeles.

3) We learn from the above sources that the translation of the Greek Aquilas for Techeles was accepted by the Midrash, and that the Aruch writes that it means hyacinth. We can now combine this with the explanation of ha'Metargem that Tosfos (Sukah 31b) also understands that Techeles is hyacinth. Ha'Metargem writes that most of the ancient scholars taught that Techeles is hyacinth color. Tosfos quite often cites the Aruch. Even though Tosfos does not actually mention the Aruch on this particular occasion, it is not unlikely that Tosfos here is following the Aruch.

Kol Tuv,

Dovid Bloom