Wash the tomatoes and bring a large pot of water to a boil. When the water is boiling, submerge the tomatoes for a few seconds to scald them and remove to a bowl of cold water to stop the tomaotes from cooking. Peel them, cut in half and remove seeds. Weigh them-for every 6 pounds of tomato pulp, you'll need 6 cups sugar and 2 cups water.
Put the water and sugar in a pot on the stove top. Stir over medium heat until the sugar has dissolved in the water, making a syrup. Bring the syrup to a boil, add the 6 lbs. tomatoes, and cook for 15-20 minutes, lowering the heat to a simmer. Be sure to watch the pot so that it doesn't boil over-it gets foamy! The foam can be skimmed off the top. After 20 minutes, turn the stove off and let the mixture sit for a few hours.
After a few hours, re-heat, stirring continuously with a wooden spoon, taking care that it doesn't stick or burn. Bring it to a boil, then lower the heat and let cook for 1-2 hours, stirring periodically. After this time, the tomatoes should have a shininess and transparent look. Stir and taste for sugar, adding more if necessary for your taste. Let cook a little bit and then put into jars or follow the canning procedure for your canning set according to manufacturer's instructions.