This video shows loading a brush with black lacquer and then applying a first coat of middle black.
For more on lacquer based kintsugi see https://zac.wnz.mybluehost.me/website_a640e8d6/

This video shows application of middle black.
For more on lacquer based kintsugi see https://zac.wnz.mybluehost.me/website_a640e8d6/