There is one historic black and white portrait of Évariste Galois that is often used . However there are a number of more recent colorful portraits that imagine him to be anything from straw blond, things in between, brown and black.
Is there any historical source that describes his hair color?
Are there arguments to that would suggest that in  his hair is not only black because of the medium such as that other hair colors like brown and blond were historically portrayed differently in that medium?
A sourced answer to any of these two questions would suffice. If there is indirect information (such as the color of the hair of his parent is verifiable to a similar standard of proof as asked for above) that is welcome too.
I am aware that modern recoloration are not a reliable source but the variety of hair color he is portrayed with suggests this fact is not know or easily googleable.
 https://fineartamerica.com/featured/evariste-galois-granger.html?product=yoga-mat (this seems to be an coloration of ) or https://www.deviantart.com/daga-ra/art/Evariste-Galois-283582290
 https://www.alamy.de/stockfoto-evariste-galois-1811-1832-franzosischer-mathematiker-leider-starb-er-in-einem-duell-im-alter-von-20-jahren-datum-1832-105254851.html (again a black and white picture in a different style) or https://www.assignmentpoint.com/arts/biography/biography-of-evariste-galois.html