HP 2300d Service Manual - Page 49

Grain field test The grain direction is usually specified on the ream label (written out "long" or "short"). The paper dimensions listed on the label also indicate grain direction. For example, the label for short-grain letter-size paper reads "11 by 8.5" and for long-grain paper reads "8.5 by 11." If the grain direction is not included on the ream label, it can be determined by using a simple wet test. Cut a small square from the corner of a sheet of paper, wet it, and observe the manner in which it curls. Envelopes should have a diagonal grain, which gives them the best stability. To determine this, cut a square section from one corner of an envelope. Wet this section and observe the manner in which it curls. Two opposite corners should curl toward each other. Figure 12. Wet test for long, short, and diagonal grain curl Curl field test To check for paper curl, place a single sheet of paper onto a flat surface and measure curl at the greatest deflection by holding a ruler perpendicular to the flat surface. Figure 13. Measuring curl ENWW 2 Installation 47