Cream together butter and sugar until light and fluffy. Add eggs, one at a time, and mix well after each addition. Mix in vanilla and almond extracts. In a separate bowl, combine flour, baking soda, cream of tartar and salt. Add, one third at a time, to butter mixture, mixing until blended after each addition. Using a wooden spoon, mix in 1/2 cup rainbow sprinkles. Refrigerate dough until chilled, or overnight.