The genuine gold leaf is for both indoor and outdoor gilding. However, for outdoor gilding, you must use 23k and above to avoid oxidisation. Genuine gold leafs are available in Transfer and Loose. The Transfer leafs are best for outdoor gilding where wind and draft make it difficult to handle the loose leafs. Transfer leaf is also best for dry gilding using Instacoll or Permacoll size. For water gilding, you should use loose-leaf, the work better on a wet surface.