See this presentation below on how to get the blue color.
- Sunlight at a specific stage.
- Making purple, then steam in a very hot temperature (or boiling water).
- R’ Toporovich – even if you take solution and boil it, turns blue.
- Multiple dipping of dye, no sunlight – gets purple. Putting another white into same solution – way to make blue, though halachic problem with ma’aris sheni.
- Dips strings should be purple with strong reactant like acetone or benzine – turns blue.
- Prof. Hoffman – when you see the glands from the snail, if you use only the bluish glands instead of purplish, you will get blue.
- Prof. Koren – there could be a murex subspecies making more blue.
- Prof. Ehud Spanier – female snails make more purple and male make more blue. Problem: snails are hermaphrodites. Gender fluid.
Dr. Baruch Sterman, Co-Founder, Ptil Tekhelet, Author, The Rarest Blue At the Ptil Tekhelet Yom Iyun Marking 25 Years Since the Renewal of Tekhelet.
Young Israel of Woodmere, May 22nd, 2016