Joe, I really like that idea!! In fact, I have to agree. I hate to think she would be fake/rebellious enough to dye her hair, and that does make a lot of sense!! 
Welcome to Pixar Planet!!
IncredigirlVirginia- Again, I feel the same way. And thank you !
Joe England- Wow. I think that explanation deserves an applause 
!!! A+ for the science buff here! That’s one of the beast explanations I’ve heard yet! I like that. And, it really does make scene! Her hair may have properties in it from her skin that give it that distinctive shine. And her having the ability to reflect light could explain that. Because, since hair is essentially dead, if it didn’t have some sort of property in it to make to go invisible with her, it wouldn’t turn invisible at all! Eee! I feel like such a science geek! My old love of my second favorite subject is coming back 
! That’s a good one! Welcome to Pixar Planet Joe England ! And thank you for the great explanation!
I never thought of that either, thank you for sharing with us!
My idea is that either her hair was brown and she died it, or one of her grandparents had black hair and the gene “skipped” one of her parents and onto her . Of course, the dying couldn’t be because one of the deleted scenes showed her as a baby with black hair. So, I personally am “sticking” to my theory of the “skipped gene”.
I’m going to remember Joe’s explanation because it’s brilliant, and doesn’t make uncomfortable at the same time!!
I dont think that Violet is adopted because when I watch the movie I see a little bit of Violet in Helens appearance and vise versa . Also there is a possibility that one of Bobs parents or Helens have black hair so Violet inherited it from her grandparents. As for dying her hair, I find that extremely unlikely considering in the movie she is only suposed to be 13-14 years old and I doubt that Helen and Bob would let her dye her hair that young. Even if she was adopted I would find it quite odd that she happens to have powers like Bob and Helen. 
It is biology possible for a child to get diffrent hair then the parants. It has something to do with the genes.
I think it’s her genes, although I wouldn’t be bothered if she had dyed her hair.
Her hair is way too shiny to be natural! But I guess it’s different for supers. I mean, maybe genes aren’t past on the way they are for as Violet would call “Normal” people. Which would also explain why each person in the family has different powers.
Very true her hair is extremely shiny but we do have to take into consideration that the movie is animated 
. I have watched the animators talk about how hard it was to animate Violets hair many times. There is a possibility that the animators werent exactly focused on how shiny it was but the way it moved.
Have you ever seen those CGI Bratz cartoons? The hair in those is so shiny and weirdly animated (sometimes their hair is more like a long blob than induvidual strands).
youtube.com/watch?v=XYqgU_5XJQI
(Turn the sound off if you don’t want to hear some of the more annoying voices)
It kind of makes me appreciate Violet’s hair a bit more.
ellie-jessie-eve: That’s an interesting theory. Yeah, I’ve wondered how the supers’ children would have different powers than their parents. It would make sense if supers pass on genes differently.
I’m glad that you agree bright dot-dasher!
But I also think it would make since that her hair was black or died it, because she kind of yearned to be normal, different from her family members. So she died her hair to distance herself and to reflect her emotions.
YD ive always wodered that YD but maybe its like a negative negative makes a positive thing YD two light colors finally made a dark one
I really want her hair to be natural. It upsets me that it would be fake, or for one of her parents to…not be her parent. That’s disgusting.
It’s still real hair.
I think she means “fake” in a sense that it isn’t naturally colored.
I think her inheriting it from another family member makes the most sense. I also think she could have dyed it- although, her eyebrows are black too, you’d think they’d be brown or blonde if it was unnatural. I think that if she did dye it, her hair was already a little darker than her mother’s.
I’m convinced that it’s natural. I can’t see her with non-black hair. It looks icky in my mind. 
I want to believe it’s natural. But I would need a biology expert to explain to me the possibilities of her having black hair.