# A B C D E F G H I J K L M N O P Q R S T U V W Y Z
Proof Staff
A proven cast-iron, steel or slate bar, ground perfectly flat, usually housed in a wooden case, used to check the working face of the PAINT STAFF.
Alternative terms
| Term | Language | Region |
| Prover | English | |
| Staff Proof (Prover) | English | |
| Steel Proof | English |
