Quick Prep Primer is an amazing tannin blocker of those Asian mahogany pieces which are notorious bleeders. One coat will generally block the tannin where 3-4 coats of BIN may be required. In some timbers (such as antique oak) you may find that the tannin may still leach through. In these cases simply apply Artisan Flat Matte Sealer to the tannin marks, dry off with a hair dryer as the faster it dries the less time there is for the water soluble tannins to leach through. Then repeat with another coat of Quick Prep.
Quick Prep is also great to increase adhesion on those shiny surfaces when using Mineral Paint, and to help with opacity when painting whites. I also like it under the more intense vinbrant colours such as bright pinks. You will find that Easy Prep seems to lock in the pigment and increases the vibrancy and opacity.