I cannot help wondering if those remaining, managed to adhere to the strict discipline of the blue stripes during those dreadful times.//Tallitot may be of any colour but are usually white with black, blue or white stripes along the edge. ... In many Jewish communities, the tallit is worn in the synagogue by all men and boys over bar mitzvah age (and in some communities even younger).// this also is the explanation given us by Rabbi Rothschild of Leeds Reform Synagogue of Roman Rd during lectures there...the mitzvah of Tzitzis in the Torah obligates one to tie four strings on the corner of a four-cornered garment. One of these strings is meant to be dyed with a blue color called ?techeles?. At some point in history, the exact identity of the ?chilazon?, the creature from which the dye is extracted, became unknown. In order to serve as a reminder of the missing aspect of the mitzvah of Tzitzis, the custom began to place blue stripes on the Talis, which eventually evolved into black stripes.... I seem to remember the very knowledgable Rabbi telling us it was a creature from the Red Sea and was an inky blue colour! hence I always paint it blue, not black.