This method describes procedures for identifying the wire side of paper made on a fourdrinier paper machine with a single wire or forming fabric. The term "wire side" will be used throughout this method and relates to the side of the sheet made in contact to either the machine wire or forming fabric.

It is not always possible to identify the difference between sides, particularly with coated and other surface-treated papers, corrugating medium, papers made with certain multiply forming fabrics, certain high-grade papers made from well-beaten rag stock, and specialties made with some variation from usual papermaking practices. Nevertheless, if any one of the following procedures gives a clear result, identification is established.

These procedures are not applicable to paper made on cylinder, twin-wire, or other machines.