The present concept is a method of preparing an egg to determine the color of the egg using an egg yolk cover. The egg yolk cover is dome-shaped with a base edge and inspection area. The egg yolk cover eliminates ambient light from impinging on the egg yolk and is used in combination with a light sensor to determine the color of egg yolks. The light sensor includes a single flat printed circuit board with a top and bottom side which includes at least one LED light and one color sensor, at least one light pipe receiving light from the LED and transmitting it onto a substrate at an angle theta and a tube frame including an optical tube for receiving light reflections from the substrate. The light pipes and the tube frame are compression fit between the printed circuit board and a lower housing. To determine the color of the egg yolk, the egg is first cracked onto a flat surface. The egg yolk cover is then placed over the egg yolk and the color sensor is placed onto the inspection area to measure the color.