Curl in cut sized paper plays an important part in how paper performs in its intended use. Frequently cut-sized papers are used in duplicators and copy machines operating at high speeds. Inherent curl, that is, curl in the ream before entering the process and curl developed during the imaging process, can affect its performance, especially if duplexing (two-side printing) or collating is involved. Common problems experienced include jamming and misregistration.

The experience used in developing the test method was limited to uncoated writing papers in the commonly used cut sizes. The technique is basic and could be used with coated papers as well as paperboard to identify the type and magnitude of curl.

The test method identifies the type and degree of curl in a pack of sheets and does not address variations that might be inherent in individual sheets. If during the testing process it is observed that one or more sheets reacts in a contrary manner to the lift, it should be noted. Curl of a single sheet may not necessarily be determined by this procedure.