In small mixing bowl, combine water, meringue powder, and cream of tarter; beat until stiff peaks form.
In separate bowl, combine powdered sugar and gum arabic; mix thoroughly, then add to meringue. Beat on low, then medium speed until stiff peaks form. Royal Icing needs to be whipped a long time; whip until fluffy and will hold shape when piped. Keep covered with a damp towel. Store in airtight, clean, greaseless container and rewhip when ready to use.
