I call no one "Doctor" unless they have a medical degree or a Ph.D. in hard math or science.
Dr. mrs. jimfree uses her title when it is appropriate to the circumstances, e.g., speaking at a conference in her field. Oh, by the way, her dissertation reports the history of the transition from natural to synthetic dyes from the 1830s to the 1880s. The study included the science of dye chemistry, economics in the industry, and popular culture evidence.