1. Bring tangerines, lemons, and water to a simmer in a large saucepan over medium heat. Cook for 5 minutes. Let cool slightly. Press parchment directly on surface of marmalade, and refrigerate overnight.

2. Remove parchment; return saucepan to medium heat. Bring to a simmer, and cook until citrus rinds are very tender, about 30 minutes. Measure mixture, and return to saucepan over medium-high heat. For each cup of mixture, add 3/4 cup sugar. Simmer until a candy thermometer registers 220 degrees, about 30 minutes. (Tangerine and lemon flesh should be broken down, and rinds should be translucent.) Plate-test marmalade to make sure it is set. Divide among 4 pint-size sterilized glass jars, leaving 1/4-inch headspace at tops. Can in water bath for 15 minutes.