Candling is a process used to determine the quality of an egg. It involves holding a strong light above or below the egg to observe the embryo. A candling lamp, which consists of a strong electric bulb covered by a plastic or aluminum, is used for this purpose. Candling is used to check for the presence of blood spots, cracks, and other defects in the egg. It is also used to determine the age of the egg and whether it is fresh or stale. Candling is commonly used in the egg industry to sort eggs into different grades based on their quality. It is an important step in ensuring that only high-quality eggs are sold to consumers.