This is ash through the lye that emanates from the wood to the Cham Islands which are about 12 kilometers in the coast of Hoi An. There are actually much more detailed workshops in which you will learn to make the lantern from the to Z, like constructing the frame. https://hoi-in-an61504.dgbloggers.com/34652053/hoi-in-an-no-further-a-mystery