Wash the oranges thoroughly, and cut only six of them into quarters.

Slice the quartered oranges into thin strips, retaining as much juice as possible while slicing.

Place the orange slices in a large saucepan and cover with water.

Over medium-high heat, bring the orange mixture to a boil, then remove from heat and let it stand, covered, overnight or at least 8 hours.

Using a small strainer or a slotted spoon, scoop the orange rinds and pulp from the mixture that has been sitting overnight, and place them in a Dutch oven or jam pot, retaining the liquid the oranges were soaking in.

Squeeze the juice from the remaining six blood oranges, and discard the rind and pulp.

Measure the juice you just squeezed, then add enough of the retained soaking liquid to make 4 cups.

Add the 4 cups of liquid to the oranges.

Squeeze fresh lemons until you have ¼ cup of fresh lemon juice, and add this to the orange mixture.

Finally, stir in the 8 cups of granulated sugar. Place the pan on medium-high heat and bring the mixture to a boil, stirring often to dissolve the sugar and prevent scorching.

Reduce the heat to medium and simmer the orange mixture, uncovered, for about 20 minutes, or until it has reached the gel stage.

Test for gel stage using the cold plate method or until a candy thermometer reaches 220 degrees Fahrenheit.

Prepare jars or containers for the jam, and prepare a hot water bath if you will can the marmalade.

Carefully ladle or pour the marmalade into jars or containers, wipe the rims with a clean, damp cloth, and put on the lids.

If canning, process in a waterbath canner for 10 minutes, or 15 minutes above 6,000 feet in elevation.