Q2. Printers Sheet?

Printer sheet is a unit of two or four panes of printing, printed simultaneously from a single plate/cylinder. These panes are separated from each other in the printers sheet by a vertical and / or a horizontal interpane gutter usually of stamp size. The marginal inscription are generally arranged on the peripheral margins of the panes of the printers sheet and the interpane gutters are usually left blank.

After the sheets has passed through the perforator, the panes are guillotined through interpane gutters, trimmed (and supplied to PO for sale).

These panes can be individually identified and their positions in the printer’s sheet determined with the help of printers imprint, sheet markings and perforation types.
Cylinder ‘numbers’ help to differentiate between consecutive printings of an issue (???)

However, in the absence of marginal inscriptions (i.e. printers, imprint and cylinder numbers) and with certain perforation types, it is not always possible to identify all the panes of a printing and their position in the printer’s sheet.