I doubt that the artist meant for the painting to be taken literally. It is a symbolic interpretation which involves much more than physical appearances. Renaissance-style art often depicted Christ with the symbolic red hair, drawing upon certain ancient customs wherein royalty and members of the privileged classes would distinguish themselves in this way. If the artist had meant for the painting to be true to literal observation, he most likely would have rendered more realistic details. See how prominent and surreal he paints the hair on Christ? To me, it almost looks like a unskilled photoshop job (believe me, I know what that looks like, lol, as I have recently been a transgressor in this area!). This comment is not meant to be a negative criticism of Bosch, but to point out that the technique is used purposely by many artists. If we look at the rest of the painting, then we can see just how symbolic it is meant to be, and so the red hair is just another element of that symbolism. These are my thoughts on the subject, anyway.
I think Jesus was both admired and despised. I imagine that there was something about His countenance and demeanor that could either disturb or comfort and inspire. Personally, I think that His clothing was probably that of a simple teacher-nothing too fancy, as I'm pretty sure He was not considered terribly affluent. I would think it would also need to be practical, considering all the traveling He did through wheat fields, in fishing boats, and down all those dusty roads. Maybe there were some symbolic reminders there, but if there were, I think it would have gone against His purpose to flaunt them. I also imagine that His mother may have made for Him a cloak of the finest design and cloth she had available, all the while pondering in her heart the beginnings of His life and the prophecies told her by the angel. There certainly could have been something unique about its construct. If the garment was to be the prize in a casting of lots among soldiers, it may very well have been because of this—probably not because the gamblers were necessarily big fans of Jesus, even though some of them might have wondered deep down in their souls.
InPeace,
InLove