During the late 1960s engineers at semiconductor companies like Intel used [[rubylith]] for the semiconductorproduction photomasksof layoutsemiconductor designlithography photomasks. Manually drawn [[Circuit diagram|circuit draft schematics]] of the semiconductor devices made by engineers were transeferred manually onto a [[Paper size|D-sized]] [[vellum]] sheeptssheets by a skilled schematic designer to make a physical layout of the device on a photomask.<ref name=":0">{{Cite journal |date=2001 |title=Recollections of Early Chip Development at Intel |url=https://deramp.com/downloads/mfe_archive/050-Component%20Specifications/Intel/Recollections%20of%20Early%20Chip%20Dev.pdf |journal=Intel technology journal |volume=5 |issue=2001 |issn=1535-864X}}</ref>{{r|:0|pp=6}}
The lattervellum would be later hand-checked and ''signed off'' by the original engineer; all edits to the schematics would also be noted, checked, and, again, ''signed off''.{{r|:0|pp=6}}
