System, including methods and apparatus, for identifying and picking spectrally distinct colonies. In an exemplary method, a filter may be received in an optical path extending from a light source to a grayscale image detector. The filter may be configured to increase an intensity difference between a first type of colony and a spectrally distinct second type of colony. Colonies including both types may be received in the optical path. An image of the colonies may be obtained with the grayscale image detector. At least one of the types of colony may be identified in the image. One or more colonies of the at least one type may be picked robotically.