Painters sometimes use color mixtures that seem far removed from the local color of actual skin.
Here’s a quick test you can do in an art museum to see what’s going on. Hold up your hand up in the air a few feet in front of the painting. (That’s my hand on the left and Jeanette’s on the right.)
This skylit gallery in the Worcester Art Museum in Massachusetts gave an even, white light. By looking at our hands under the same light, we now have a reference point to evaluate the color mixtures.
This painting is by the British portraitist Sir Joshua Reynolds (1723-1792). It must have been fashionable in his day to have what seems to us a sickly pallor. In this case he painted the portrait well to the gray-green side of our skin tones.
Addendum: According to the website "Pigments through the Ages," Reynolds used the pigments "lead white, yellow ochre, ultramarine, orpiment, carmine lake, Naples yellow, and vermilion."
"Today many Reynolds’s portraits show pale faces. It’s known that even in his lifetime his paintings began to fade. Using transparent glazes over a monochrome under painting, he tried to reproduce the effects of Italian old masters, but the pigment he used for his flesh tones was not permanent and faded.