According to embodiments, an image reading apparatus and an image reading method are disclosed. The image reading method comprises receiving a signal of an image color of an image on an original, and based on the received signal, controlling an illuminating section comprising a red light source, a green light source and a blue light source so that one of the red, green and blue light sources is turned off, while the remaining light sources are turned on. The image reading method further comprises receiving, on an image sensor, light from the turned-on light sources that is reflected off of the original, and processing the light received by the image sensor to form a monochromatic image.