I don't have the background to answer your question directly, but you might find these two previous answers helpful:

When did Jesus start being portrayed as white? by /u/sunagainstgold,

And

When did artists first start portraying Jesus with shoulder-length hair and a beard? Is there any historical basis for portraying him in such a way? by /u/thepibbs.

Definitely not discouraging any new answers, just came across those two answers by chance earlier today and thought I'd share past answers.