This lecture covers the fundamental concepts of microscopy resolution, focusing on the difference between ideal and real image formation, the impact of aperture on resolution, and the role of numerical aperture in enhancing resolution. It also delves into the principles of bright-field microscopy, emphasizing the importance of contrast and resolution trade-offs. Furthermore, it explores dark-field microscopy as a technique to enhance contrast for transparent specimens, detailing the setup and advantages of this method. The lecture concludes with a discussion on Rheinberg illumination, a specialized dark-field variant that uses colored stops to create striking color contrast in microscopy.