Yes, it is necessary for any ties with dot designs to have only two colors. The sizes of dots, few experts might ignore. But most tie experts will call for similar sizes of dots of same color on contrasting colored background is a polka dot tie. If we try to define the polka dot ties then we get ties with two contrasting colors only where the dots are of equal size in all over direction with regular neckties shapes and sizes are called polka dot ties. These ties are growingly popular among men. Do you have polka dot ties ? Buy some polka dot ties as they are necessary wear for any relaxed get together party.