Gum ammoniac is a natural gum size harvested from dried tree sap that has been processed to a traditional recipe. It has enough flow to be used with a dip pen or a brush and is best suited to small or fine work. For very detailed work you may need two applications, especially if the paper is absorbent. Gum ammoniac can be built up to achieve raised areas but not to the same extent as gesso or Improved Gold Body.
Once applied and left to dry the gum can be reactivated by breathing onto it before pressing the gold down onto the tacky gum. Allow at least five minutes before burnishing and do not burnish directly onto the leaf, instead use glassine paper between the gold and the agate burnisher. You should find that using gum ammoniac as a size allows for a brighter burnished finish than the Ormoline Gilding Medium or Water Gold Size.
Important: Gum Ammoniac sets hard, quickly; so if you don't want to ruin your pen or brush immediately wash them in hot water after use!