Editing Mimeograph (section)

===Limitations===
Unlike spirit duplicators (where the only ink available is depleted from the master image), mimeograph technology works by forcing a replenishable supply of ink through the stencil master. In theory, the mimeography process could be continued indefinitely, especially if a durable stencil master were used (e.g. a thin metal foil). In practice, most low-cost mimeo stencils gradually wear out over the course of producing several hundred copies. Typically the stencil deteriorates gradually, producing a characteristic degraded image quality until the stencil tears, abruptly ending the print run. If further copies are desired at this point, another stencil must be made.

Often, the stencil material covering the interiors of closed [[letterform]]s (e.g. ''a'', ''b'', ''d'', ''e'', ''g'', etc.) would fall away during continued printing, causing ink-filled letters in the copies.  The stencil would gradually stretch, starting near the top where the mechanical forces were greatest, causing a characteristic "mid-line sag" in the textual lines of the copies, that would progress until the stencil failed completely. 

The [[Gestetner]] Company (and others) devised various methods to make mimeo stencils more durable.<ref name=DupStencil>{{cite web |title=Duplicating stencil |url=http://www.patentstorm.us/patents/4535690/description.html |archive-url=https://archive.today/20130421191131/http://www.patentstorm.us/patents/4535690/description.html |url-status=dead |archive-date=2013-04-21 |work=Patentstorm |access-date=2011-05-10}}</ref>

Compared to spirit duplication, mimeography produced a darker, more legible image. Spirit duplicated images were usually tinted a light purple or lavender, which gradually became lighter over the course of some dozens of copies. Mimeography was often considered "the next step up" in quality, capable of producing hundreds of copies. Print runs beyond that level were usually produced by professional printers or, as the technology became available, [[xerography|xerographic copiers]].