Wash your canning jars well in hot water. Be sure you have enough lids on hand.
1/2 bushel Roma tomatoes yields about 27 pints.
Canning is a labor of love - seeing the results is a pleasure. Eating summer's sun-kissed harvest in the middle of the winter is a joy.
Assemble clean jars, lids, screw rings, clean dish towels, pressure cooker, canning tongs (to lift jars), colander, paring knife, medium size bowl, medium size pan, ice, salt, 1/2t. measuring spoon, butter knife, measuring cup.
Wash the tomatoes off under running water, place in colander. Boil water in medium size pan, 2/3 full. Put 4 c. of water in bottom of pressure cooker, and put the rack in (upside down). Fill medium bowl 2/3 full with water and ice to make ice water. Spread clean dish towels on the counter top.
Dip tomatoes into boiling water a few at a time, for 1 minute. Immediately put them in the ice water to loosen the skins. Peel the skins off, trim out any bad spots, cut in half, place into jar. Press the tomatoes together tightly in the jar so that juice forms, filling to within 1/2" of the top, and using the butter knife around the sides to remove air pockets. Carefully wipe the edge of the jar clean, add 1/2 t. salt to each jar. Put on lid and screw band, firmly, but not over tight.
Place 4 jars at a time into the pressure cooker, at 5 lbs pressure. Process for 10 minutes after the pressure regulator jiggles. Important: cool the pressure cooker for 10 minutes before you gently test the regulator to expel any remaining steam.
Carefully remove the jars with the canning tongs, being careful not to touch the rings or lids, and being careful to avoid burns. Place the jars immediately onto the clean dish towels to cool, with about 2" of space in between the jars. You will probably hear the "ping" of the jars as they seal. Let them cool a few hours and then check the seals. Any unsealed jars should be reprocessed (after cleaning the top edge and lid), or placed in the refrigerator to be used.