The red wavelengths of light are the longer wavelengths and the violet wavelengths of light are the shorter wavelengths. Between red and violet, there is a continuous range or spectrum of wavelengths.
The USPS also includes that a large postcard is 49 cents to mail. The maximum size for this postcard is 11 1/2 inches long, 6 1/8 inches high and 1/4 inch thick. This is the same rate to mail a First Class 1 ounce letter domestically. The rates for postage increased as of January 2014.
$0.34 Cent Postcard Stamps. If you are mailing your wedding-themed postcards After April 10th 2016 then you will need a 34 cent stamp to mail it 1st-class (The price recently decreased from $0.35 to $0.34). Be sure to double-check the weight and size of your postcard with your local USPS post office.