Solder Resist Is an ink-based liquid applied using either Air spray or Screen printing. It is applied as a permanent layer which protects copper from corrosion and aids assembly. The standard colour for PCBs is green, but there are many other colours available including; black, blue, red and high white. Solder resist can also be supplied in matt, semi matt, or a gloss finish.
Also known as component reference of CompRef, as with solder mask this can be applied either by air spray or screen printed. Standard notation is white, but again a wide range of colours are available.