ReNae - Just a quick thought. When you're dealing with aged resource photos that are missing the color information you need for a color oil painting, you might first use a simple tonal medium to explore your subject - look at this beautiful
drawing recently posted by Deladier.
You might find graphite, charcoal, sauce, conte or pen and ink as a better medium choice; anything that would allow you to explore the information that you do have available in your source.
Sometimes very simple tonal images can be quite powerful and you won't be in the impossible position of adding imaginary colors and color temperatures when you're portraying a subject in a realistic manner.