The difference between rods and cones

There are two types of photoreceptors in the human eye, rods and cones.  They are located on the retina.  They are each responsible for decoding the image received from the retina for the brain to take in as electrical signals.  Rods take in light at low levels.  This is known as scotopic vision.  This is what helps us to see at night.  If the rods were capable of taking in color as well, we, as human beings would have the ability to see at night, just as we do in the day time.  However, rods do not decode color.  That is what cones do.  Cones decode color at high light levels.  This is known as photopic vision.  This explains why color is harder to take in at night, and shapes stand out.