A tightening key is a small wedge or shim used in the construction of a canvas stretcher frame with expandable joints. The key is inserted into the slotted inside the stretcher bars at the mitered corners of the frame to prevent or adjust sagging.[1][2][3] Tightening keys are commonly made in plastic or wood, and are often called corner keys or corner wedges.[3] Tightening keys were introduced in the mid-18th century, making expandable (versus rigid) stretcher frames possible.[4]

The back of a stretched canvas, with keys inserted at the corner, and additional keys off to the side.

Most stretcher frames have eight keys, two in each corner.[1] Each key is tapped in to expand the stretcher bars slightly, tensioning the canvas.[1][2] The keys can be used to re-tighten the canvas as it relaxes naturally over time.[5] If the key is tapped too forcefully, it may tear the side of the canvas.[4] Conversely, keys that become too loose can fall out during handling and damage the painting's surface.[1] The process of inserting keys into the stretcher is called "keying-out."[4]

Types

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Corner keys or wedges come in various forms. Most are manufactured for a specific size stretcher bar, making framers and artists hold various sizes in stock. A product called "wedgee" eliminates the need to stock many types as it has a male / female profile, which allows it to be pressed together to fit most corner cut-outs.[citation needed]

See also

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References

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  1. ^ a b c d Basic condition reporting : a handbook. Deborah Rose Van Horn, Heather Culligan, Corinne Midgett, Southeastern Registrars Association (4th ed.). Lanham, Maryland. 2015. p. 77. ISBN 978-1-4422-4770-3. OCLC 894625590.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)
  2. ^ a b The preservation management handbook : a 21st-century guide for libraries, archives, and museums. D. R. Harvey, Martha R. Mahard, Donia Conn (2nd ed.). Lanham, Maryland. 2020. p. 317. ISBN 978-1-5381-0900-7. OCLC 1121443778.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)
  3. ^ a b Friel, Michael (2010). Still-life painting atelier : an introduction to oil painting (1st ed.). New York. p. 48. ISBN 978-0-307-82878-1. OCLC 897376626.{{cite book}}: CS1 maint: location missing publisher (link)
  4. ^ a b c Tsang, Jia-Sun; Madruga Carvalho Caldeira, Ines; Williams, Don; Pelasara, Rick; Patterson, Robert (2013). "Modernized Stretcher for Paintings on Canvas: Assessment and Observation" (PDF). Postprints. 26. American Institute for Conservation of Historic and Artistic Works: 91–92.
  5. ^ MacFarlane, Rachel (2017-05-26). "A Painter's Guide to Stretching Canvas". Format Magazine. Retrieved 2022-09-29.