Intaglio n. (pl. E. intaglius, It. intagli) A cutting or engraving; a figure cut into something, as a gem, so as to make a design depressed below the surface of the material; hence, anything so carved or impressed, as a gem, matrix, etc.; opposed to cameo. Also used adjectively.
... situated at the south end of the edifice. The dust of ages was thick upon it and so concealed the characters as to make them well-nigh invisible. With care I washed the slab, then with black crayon darkened its surface until the intaglio letters appeared in white on a dark background. (The photographs of this inscription can be seen at Mr. ... — The Mayas, the Sources of Their History / Dr. Le Plongeon in Yucatan, His Account of Discoveries • Stephen Salisbury, Jr.