I would only open up 1.5 stops for a caucasion face. That being said and your model not being caucasion, throw that out the window..... I would compensate +1 if you wanted her face to be the focus (haha!!) of correct color rendition.(posted 8834 days ago)The compensation you need for print film is the same you would use for slide film. I personally only compensate with negs when I am shooting into harsh backlit situations. But I compensate everything with slide. I mean everything. If there is more than 50% of black or white or sky in the frame I compensate. Closer to 75% I compensate more.
I would use a gray card and spot meter off of it. Get right up next to it if need be. I assume you're shooting outdoors.....?
This would be a good time to test your camera's meter against the spot meter (or vice versa).
I'll add some personal experience to sign off. For the longest time (12 months actually) I had to bracket everything when shooting slide. I've got 70-75 rolls with very few "different" shots on each roll. Tons of bracketing. Like + or - 2 in both directions. In addition I rated everything 1/3 over for safety. I am now confident in my metering skills and I know what my camera will do in it's 9.5% partial spot mode (Elann IIe) and I NEVER underexpose any longer. I am done bracketing except in very once in a lifetime circumstances. You too can achieve this with practice (lots of bracketing) and careful notes. Good luck and let us know how it turns out.