Paper weight is one of the most frequently misunderstood specifications in office and stationery purchasing. The number printed on a ream of A4 paper — 80 g/m², 90 g/m², 100 g/m² — directly affects how paper behaves in a printer, how ink sits on the surface, and how the finished document feels in the hand.
Stationery goods including paper — Wikimedia Commons, CC BY-SA
What GSM Means
GSM stands for grams per square metre. It is the standard unit for measuring paper weight defined by the ISO 536 standard. A single sheet measuring exactly one square metre is weighed, and that weight in grams is the GSM value.
This means GSM is independent of sheet size. Whether you are buying A4, A3, or A5 paper, the GSM value describes the same physical property — the density of the paper stock. A ream of 80 g/m² A4 paper and a ream of 80 g/m² A3 paper are made from the same stock; the A3 sheets simply contain twice the material per sheet.
The ISO 536 standard defines paper grammage as the mass per unit area, expressed in g/m². This is the basis for all paper weight specifications used in European office and commercial printing contexts.
Common Paper Weight Ranges
Office and stationery paper in Poland typically falls within a predictable range. The following categories describe how different weights behave in practice:
| Weight (g/m²) | Common Name | Typical Use |
|---|---|---|
| 60–70 | Lightweight / Thin | Tracing paper, internal drafts, airmail paper |
| 75–80 | Standard Copy | Everyday office printing, photocopying |
| 90–100 | Premium Copy / Writing | Correspondence, letterheads, official documents |
| 120–160 | Light Card / Cover | Covers, menus, certificates, postcards |
| 200–300+ | Card / Board | Business cards, presentation folders, packaging |
80 g/m² as the Office Standard
In Polish offices, 80 g/m² is the default. Most laser printers and inkjet printers sold for office use are optimised for this weight. It feeds reliably through automatic document feeders, duplex units, and standard paper trays without jamming or curling under normal humidity conditions.
Major Polish office supply retailers stock 80 g/m² A4 reams as their volume product. Suppliers such as Leroy Merlin, Papiernia, and national distributors serving the public sector consistently list 80 g/m² as their baseline specification.
The limitation of 80 g/m² paper is show-through: when printed on both sides, text or images from one face are faintly visible through the reverse. For single-sided documents this is irrelevant. For double-sided printing of contracts, reports, or academic papers, a step up to 90 g/m² is often worthwhile.
When to Choose 90 or 100 g/m²
Moving from 80 g/m² to 90 g/m² reduces print-through noticeably. The tactile difference is also apparent — 90 g/m² paper feels stiffer and less prone to buckling when written on with a fountain pen or rollerball.
100 g/m² paper is used for correspondence that needs to convey quality: formal letters, invoices sent to clients, or official internal communications in larger organisations. It is also the minimum recommended weight for letterhead printing, where the stock is a deliberate part of the impression made on the recipient.
Implications for Inkjet Printing
Inkjet printers deposit more liquid ink per page than laser printers. On lightweight (60–75 g/m²) paper, inkjet ink can cause visible wrinkling or feathering at the edges of text. Using 80–90 g/m² paper specifically rated for inkjet use (often labelled as "inkjet paper" or with a brightness rating above 160 CIE) improves output quality measurably.
Paper Weight and Handwriting
For notebooks and writing pads, paper weight interacts with pen type in a way that printing does not. A fountain pen nib deposits ink differently from a ballpoint, and the paper surface — not just its weight — determines whether the ink bleeds, feathers, or sits cleanly on the page.
Most standard ruled notebooks available in Polish newsagents and office supply shops use 70–80 g/m² paper. This is adequate for ballpoint and most rollerball pens. For fountain pen use, papers rated at 80 g/m² or above with a smooth (low-roughness) surface perform significantly better. Brands such as Clairefontaine (available through import) and Navigator (widely stocked in Poland) produce smooth-surface 80 g/m² paper appropriate for fountain pen writing.
Brightness and Whiteness
Paper weight is sometimes confused with paper brightness. These are separate properties. Brightness is measured on the ISO 2470 scale (or the older CIE scale) and describes how much light the paper reflects. Higher brightness numbers produce higher contrast against dark ink, which is particularly relevant for fine print and small-scale typography.
Standard office paper in Poland is typically rated between 146 and 161 CIE brightness. Premium stationery paper often reaches 165+ CIE. Brightness does not directly affect paper strength or printability — it only affects visual contrast.
For most office purposes in Poland, 80 g/m² paper at 160 CIE brightness covers the majority of use cases. Stepping up to 90 g/m² is worthwhile for double-sided printing; stepping to 100 g/m² makes sense for formal correspondence and letterheads.
Sources and Further Reference
The ISO 536 standard for paper grammage is published by the International Organization for Standardization and is referenced by European paper manufacturers. The ISO 216 standard governs the A-series paper sizes used in Poland and across the EU.
Public documentation on these standards is available through the ISO website. The Polish Standards Institute (PKN) also maintains local versions of European paper standards.