Color Portrait from Black & White Photo

[Lara Cannon]

I am working on an oil portrait that was commissioned from a black and white photograph. The woman died many years ago so the only photos I have are black and white. I know I shouldn't have said "I can do it", but I did. So now I find myself really struggling to make realistic flesh tones.

She is outside, wearing a turquoise dress and she had dyed blond hair. I was able to pull off the dress and hair but the skin is a muddy mess! I have searched the Internet and this forum for solutions. I found some suggestions for a limited palette (Venetian Red, Indian Red, Yellow Ocher, Raw Umber, Ivory Black & Flake White + Ultramarine Blue, Alizarin & Viridian Green).

But I am hoping to get an even simpler formulaic solution, like a flesh tones for dummies perhaps? I hope there might be a sure-fire paint by the numbers solution that will make a generally believable Caucasian blond female?

Any suggestions would be greatly appreciated!
Lara