Baking Tips of the day: Cake flour versus self-rising flour.
They are not the same.
Cake flour is a light, delicate, finely milled flour. It has a lower protein content than its all-purpose which means any batter you make with it won't develop very much gluten, and your finished product will be lighter and softer, with a finer crumbs.
Substitute Formula: Cake flour = all purpose + cornstarch or arrowroot
Self-rising flour is almost exactly like all-purpose flour, but it has added salt and leavening mixed into it. Recipes that call for this type of flour typically won't require additional salt or leavening. You should never substitute self-rising flour in place of all-purpose flour as the amount of leaveners.
Formula:
Self-rising flour = all purpose flour + baking powder + salt