Paper Weight - Let’s End the Confusion
Understanding paper weight can be challenging due to varying standards and terminology. This guide clarifies key definitions and provides a comprehensive comparison table of equivalent weights across paper types.
Definitions:
Basis Weight
Basis weight is the designated fixed weight of 500 sheets, measured in pounds, in that paper's basic sheet size. The basic sheet size differs among paper types.
Caliper
Caliper refers to the thickness of a sheet of paper, expressed in thousandths of an inch, as measured by a micrometer. Standard paper caliper should not exceed a ±5% variance within a sheet. Generally, a greater caliper (thicker paper) corresponds to a greater paper weight.
Equivalent Weight
Although different paper types have different basic sizes, they can be compared using equivalent weight.
Basis Weight ("Category") Table
| Type Paper | Basic Size - 500 Sheets |
| Bond: Ledger, Mimeo, Duplicator, Rag Paper | 17" × 22" |
| Offset: Book, Text, Coated Paper | 25" × 38" |
| Cover | 20" × 26" |
| Tag Stock | 24" × 36" |
| Index | 25-1/2" x 30-1/2" |
The values in the following table serve as a guide only. They are not specifications, as variances occur within the same basis weight due to other paper characteristics. Similar weight papers may also vary between manufacturers.
| Bond Ledger | Offset Text | Cover | Tag | Index | Points | *Caliper(inches) | millimeters | Metric(grams/sq meter) |
|---|---|---|---|---|---|---|---|---|
| 16 | 40 | 22 | 37 | 33 | 3.2 | .0032 | 0.081 | 60.2 gsm |
| 18 | 45 | 24 | 41 | 37 | 3.6 | .0036 | 0.092 | 67.72 gsm |
| 20 | 50 | 28 | 46 | 42 | 3.8 | .0038 | 0.097 | 75.2 gsm |
| 24 | 60 | 33 | 56 | 50 | 4.8 | .0048 | 0.12 | 90.3 gsm |
| 28 | 70 | 39 | 64 | 58 | 5.8 | .0058 | 0.147 | 105.35 gsm |
| 29 | 73 | 40 | 62 | 60 | 6 | .0060 | 0.152 | 109.11 gsm |
| 31 | 81 | 45 | 73 | 66 | 6.1 | .0061 | 0.155 | 116.63 gsm |
| 35 | 90 | 48 | 80 | 74 | 6.2 | .0062 | 0.157 | 131.68 gsm |
| 36 | 90 | 50 | 82 | 75 | 6.8 | .0068 | 0.173 | 135.45 gsm |
| 39 | 100 | 54 | 90 | 81 | 7.2 | .0072 | 0.183 | 146.73 gsm |
| 40 | 100 | 56 | 93 | 83 | 7.3 | .0073 | 0.185 | 150.5 gsm |
| 43 | 110 | 60 | 100 | 90 | 7.4 | .0074 | 0.188 | 161.78 gsm |
| 44 | 110 | 61 | 102 | 92 | 7.6 | .0076 | 0.193 | 165.55 gsm |
This evolution supports more precise paper specification and usage. Furthermore, the integration of sustainable practices remains a significant focus across the sector.
| 0 Comments |
|---|