First, the transfer film is gently attached to the engraved scarlet letter (not separated from the whole paper), and the required scarlet letter is extracted with the transfer film and attached to the good position of the white character (engraved but not separated from the whole paper); Then the scarlet letter and white characters are extracted together with the transfer film, and then pasted on the glass. After the alignment, the characters are flattened and the transfer film is removed. The transfer film can be reused.