[Sca-cooks] Ratio needed

[Christine Seelye-King]

Can someone tell me what the formula is for self-rising flour?  I know it
means the addition of baking soda and powder, but I don't know how much of
each (say, to one cup of flour, or one pound, or whatever measurements
you've got it in, I can take it from there.)  I want to make the Guiness
cake for my lord's birthday this weekend (since I'll be going off to attend
the Pelican retreat - hooray - I'll be missing most of his natal day,
figured I'd leave him with the cake and the rest of the Guiness :), and I
never buy self-rising, which is called for in the recipe.
Thanks,
Christianna