Tula niello — *chern* — is the pre-1900 Russian craft of engraving silver and flooding the incisions with a black sulphide alloy. Fired into the metal, it renders cityscapes, cartouches and scrollwork as fine silver line-work caught against a dense, matte field.

The authoritative tone is never jet-black but a dark grey-black with a faint cool blue cast. This system distills that high-contrast metal relief into a screen language: bright burnished silver drawn over a blue-black niello ground, strictly monochrome, no colour beyond the silver-to-niello range.