objective lens color codes

Colors painted on the objective lens body to indicate the specified magnification and immersion media. Some common colors are 4x - red, 10x - yellow, 20x - green, 40x - light blue, 60x - dark blue, 100x - white. Immersion color codes are painted between the magnification color and the tip of the objective lens. Some common immersion color codes are oil - black, water - white, and special (such as silicone oil) - red.