What is a slate?

Buy a piece of plexiglass (chemical name: polymethylmethacrylate), black or white, draw according to the layout (that is, directors, photographers, etc.), carve a self-adhesive with laser lettering (graphic shops can generally do it), stick the carved self-adhesive on the plexiglass, tear off part of the words, then coat it with organic solvents such as acetone or chloroform (solvents will corrode the surface without self-adhesive), and then wash it with water later. Tear off the glue after solidification, and the words will be corroded, so that the words on it will be more beautiful, similar to industrial products. The key is to master the time of solvent corrosion.