Melt the butter in a large pot over moderate heat. Add the rice and stir until the grains are coated. Add the water, cinnamon, turmeric, saffron, sugar and salt. Stir well, and bring to a boil over high heat. Reduce the heat to low, then sprinkle the raisins on top of the rice. Cover the pot with lid and simmer for about 20 minutes or until the rice is tender and has absorbed all the liquid. Remove rice from the pot and place in serving bowl.