What does gsm mean?
Gsm stands for grams per square metre. It is the weight of a single sheet of the paper measuring one metre by one metre. Because it is based on area, it lets you compare papers fairly regardless of sheet size or roll width.
A quick way to picture it: an A0 sheet is one square metre, so a sheet of 90gsm CAD paper at A0 weighs 90 grams. An A4 sheet is one sixteenth of a square metre, so standard 80gsm office paper weighs about 5 grams per sheet.
Weight is not the same as thickness
Heavier paper is usually thicker, but not always in proportion. Thickness (often called calliper) depends on how the paper is made and finished. A dense, smooth coated paper can be thinner than a bulky uncoated one of the same gsm. Coatings also add weight. So gsm tells you a lot, but it is worth checking the datasheet or feeling a sample if thickness or stiffness really matters.
What weight affects
- Opacity. Heavier papers generally let less show through from the reverse, which matters for double-sided printing.
- Stiffness and feel. Heavier stock feels more substantial and holds its shape on display.
- Ink handling. Heavier papers, and coated ones especially, tend to cope better with heavy ink coverage without cockling.
- Printer compatibility. Every printer has a maximum media weight and thickness. Always check your printer’s specification.
- Handling and postage. Heavier rolls and sheets weigh more to store, carry and post.
Typical uses by weight band
| Weight band | Typical uses | Pluss examples |
|---|---|---|
| Lighter (around 80–90gsm) | Office printing, CAD line work, check plots | Pluss uncoated 90gsm, MIDCOL 90, Premium Coated CAD 90 |
| Mid-weight | Posters, presentation prints, graphics | Pluss graphics media, HP graphics media |
| Heavier | Photographic prints, display, fine art | Rauch PMC 230 (230gsm satin photo paper), PremierArt |
Choosing the right weight
- Start with the purpose: a quick check plot, a client presentation or a print for the wall.
- Consider how it will be handled, displayed or mounted. Mounted prints can often use a lighter paper, because the board provides the stiffness.
- Think about ink coverage. Heavy colour fills call for a coated, often heavier, paper.
- Check your printer’s maximum media weight and thickness.
- Test a sample with your own files before ordering in volume.
Tip: Gsm is only half the story. Coating and finish often make more difference to print quality than a few extra grams. See choosing CAD paper and choosing wide-format media.
Ask for advice
Not sure which weight suits your job? Call 01252 624411 or email sales@landoruk.com for advice, sizes, pricing and availability.