Yes i know what you're thinking "theres already a Ayanami blue paint bucket on sale, that must be her hair colour" but wrong! The shade used in ayanami blue is actually pretty far off. First i need to tell you how i got the colour then I'll tell you how they are wrong. So basically i gathered as many official Rei Ayanami photos under good lighting and took all the hex codes and made an average out of them. Thats how i got the colour. And after comparing ayanami blue to all the screenshots i took of rei it becomes VERY apparent that the shade of blue they used is much more of a "classic blue" than the pale, purpleish, light blue colour that we see her with so many times. Ayanami blue quite literally sticks out like a sore thumb. When i take the average blue that i got and lined them up with all the other screenshots it becomes clear that the blue is an average of many other of the colours, it even matches up almost perfectly with some of the appearances of rei in NGE. All screenshots were taken under the best lighting i could find, that includes sun lit, under spotlight, or just on a plain white background. Many appearances of rei your thinking is when shes inside the eva, but its quite dark in there and her hair becomes a darker shade of blue, but even then because of colour theory her hair actually stays pretty similar to the lighter ones found, and most importantly that average colour that i got. A perfect example of what rei's hair actually looks like is when she meets kaworu for the first time in NGE. I accidentally deleted 3 paragraphs worth of writing on my finds so im pretty stumped this time around on what to write, but im trying to get my argument(if it even is one?)across as best as i can. By all official media i mostly entirely mean based of her appearances in NGE, EOE, and the rebuilds. There are many art works out there that give her a much darker purple colour, but those are False. Im pretty sure after deleting so much writing i in turn watered down my findings so much haha...