In a handpress, this lightweight hinged frame attaches to the tympan. The operator covers it with a sheet of heavy paper and cuts out windows exactly where the type will strike. When folded down over the blank sheet, it holds the paper securely in place and prevents the margins from picking up stray ink from the furniture or chase.
Cut the frisket a little wider on the gutter side so it doesn't mask the folio numbers.
If your margins are picking up ink smudges, your cutout windows are likely too wide or the paper has stretched.
Related terms
Tympan
The padded frame or sheet on a letterpress that holds the paper against the inked type.
Handpress
A manually operated printing machine that applies pressure to ink and paper.
Furniture
Blocks of wood or metal used to fill blank spaces in a chase and establish page margins.
Chase
A heavy steel or iron frame used to hold metal type and blocks securely together for printing.