Print materials and weights: a practical guide.

What gsm actually means

Grams per square metre. That’s it. A 300gsm sheet weighs 300 grams per square metre of surface area. Higher number, heavier paper.

It’s the print industry’s version of thread count in bedsheets. A rough indicator of substance and quality, but not a guarantee of either. Two 300gsm sheets from different mills can feel completely different in the hand depending on the fibres, calendering, coating and finish. The number tells you something. It doesn’t tell you everything.

In practice, gsm is most useful as a shorthand. It lets a printer and a customer agree on a ballpark weight without having to physically compare samples. As soon as quality matters, sampling beats specifying.

Why heavier isn’t always better

Think of a car. A heavier car isn’t a faster car. A heavier car isn’t even necessarily a safer car. It’s just a heavier car. Same with paper.

The most common upgrade customers ask for — going to the highest available gsm because it sounds like the premium option — often produces a worse result, not a better one. Business cards at 600gsm can feel awkward in a cardholder. Flyers at 250gsm cost double for no real perceived benefit. Posters at 350gsm tear themselves under their own weight on a wall.

The honest pattern across most print products is this: there’s a window of weights that work for the job, the difference between options inside that window is small, and going outside that window in either direction creates problems. Too light and it feels cheap. Too heavy and it doesn’t function properly or just wastes money.

The difference between 100gsm and 200gsm is significant. The difference between 300gsm and 400gsm in the same product type — often not really. Between 100gsm and 400gsm, you’d feel that immediately. The midrange jumps are where customers spend money for marginal returns.

Coated vs uncoated

Coated paper has a layer of fine clay, calcium carbonate or polymer sealed onto the surface. Uncoated is just the raw fibre. The coating makes the surface smoother, more uniform, and less absorbent — which is why coated paper holds ink crisply and reproduces colour better.

For most printed products in South Africa, coated is the default. Business cards, flyers, brochures, posters, postcards — coated stocks reproduce photos and brand colours more accurately. Uncoated paper absorbs ink, which softens colours and can make small text look fuzzy.

Where uncoated wins: anywhere you’ll be writing on it, anywhere a tactile natural feel matters (letterheads, invitations, design-led brand work), anywhere you want recycled or eco credentials. Uncoated also has an aesthetic — design studios in Cape Town and Woodstock have made it a calling card for boutique brands.

For outdoor work and large format, “coated” takes on a different meaning. PVC banner vinyl and printable canvas are almost always coated because uncoated versions don’t accept the inks properly. Sometimes a printer will recommend an additional UV coating on top, especially if they’re using cheaper inks or if the print needs to last in harsh sunlight. That’s a separate decision from coated vs uncoated paper.

Gloss, matte and silk finishes

These are the three finish categories you’ll see most often in SA quotes. They describe how the surface reflects light, not the paper underneath.

Gloss is shiny. Photos pop, colours look saturated, the surface reflects light strongly. Good for products where vibrancy matters more than readability. Downside: glare under direct light, fingerprints show, and on very glossy uncoated finishes the gloss can rub off over time. For anything where gloss really matters, the paper needs to be coated underneath to keep the gloss durable.

Matteis non-reflective. Photos look slightly softer, text reads cleanly, no glare. Tends to feel more premium in the hand because matte surfaces don’t telegraph “cheap printing” the way bad gloss does. Picks up scuffs more visibly than gloss in some stocks.

Silk sits between the two. Slight sheen, slight reflection, no full gloss. Often used for menus, programmes, brochures and other things that need to feel substantial without looking cheap-shiny.

The honest answer to “which is best” is that it’s personal preference. Matte business cards with a glossy laminated vinyl banner outside — a reasonable combination. Glossy business cards with a matte interior signage system — also reasonable. The finish is a styling choice more than a technical one, and the only wrong answer is choosing something that doesn’t suit how the printed item will actually be used.

Business cards: a brief note

Business card weight is one of the few cases where a little extra gsm meaningfully changes how the product feels in the hand. A 300gsm card feels reasonable. A 400gsm card feels deliberate. There’s an actual perceptual difference, unlike the difference between a 300gsm and 350gsm flyer where almost nobody could tell which is which.

That said, more weight stops paying off above about 400–450gsm for most jobs. Cards above 500gsm start fighting the printer’s cutting machines, struggle to fit in standard cardholders, and feel like coasters more than cards.

Common SA finish combinations: 350gsm matte laminated (the everyday premium), 400gsm uncoated for design-led brands, 450gsm with spot UV or foil for genuinely premium executive cards. Soft-touch laminate has become popular over the last few years and adds a velvety hand-feel that customers notice immediately.

Flyers: the 135gsm question

The classic budget vs premium decision in SA flyer printing. Common options are 135gsm gloss, 170gsm silk, 250gsm card and 300gsm postcard stock.

135gsm is the workhorse and it’s genuinely fine for almost all promotional flyer work. Standard handouts, event marketing, mailer drops, point-of-sale takeaways. People often assume they should upgrade because it sounds like the cheap option, but a well-printed 135gsm flyer in vibrant colour does the job and doesn’t feel cheap unless the design lets it down.

170gsm is the middle ground worth paying for when the flyer will be held and read for longer than a few seconds — menus, programmes, more considered marketing. It feels noticeably more substantial. Beyond about 200gsm you’re in postcard and direct-mail territory, which is a different product with different rules.

And a useful rule: higher gsm does not mean better paper. A premium-quality 135gsm stock from a good mill will outperform a generic 170gsm stock in colour reproduction, crispness and feel. The number is one factor, not the only factor.

Posters and large format

For posters, the working rule is: the larger the poster, the higher the gsm should be. An A3 poster on 135gsm is fine. An A0 poster on 135gsm is a tearing accident waiting to happen — the paper can’t support its own weight when mounted with tape or pins along the top.

Rough guide for indoor poster work: A3 and smaller can comfortably run on 150–170gsm. A2 wants 170–200gsm. A1 and A0 usually need 200–250gsm to handle being moved, mounted and stored without creasing or tearing along the edges.

Cost matters too. A run of fifty A1 posters at 250gsm is significantly more expensive than the same run at 170gsm — both in materials and because heavier paper sometimes prints slower and uses more ink. For short-term campaign work, 170gsm is often the sensible middle.

Outdoor or weather-exposed posters move into a different category entirely. Standard paper, even heavy stock, doesn’t survive rain or wind. Outdoor work goes onto PVC, vinyl or weather-resistant synthetic stock instead.

Photo paper: where weight myths live

Photo paper is the product where the “heavier is better” assumption is loudest and most wrong. Customers see 250gsm photo paper next to 170gsm photo paper, assume the heavier option is automatically superior, and pay the upgrade.

In reality, what makes photo paper good is the coating layer that receives the ink, not the substrate weight. A well-coated 170gsm photo paper from a good supplier will out-perform a poorly-coated 250gsm photo paper from a cheaper one. The 250gsm will feel more substantial in the hand. The 170gsm will produce better-looking prints.

The honest practical advice is two-fold. If you care about how the print looks, ask the printer for a sample of their photo stocks before committing — the difference between two photo papers at the same weight from different mills can be dramatic. If you can’t sample, default to the printer’s recommended premium stock at a reasonable weight (usually around 220–250gsm). It’s the peace-of-mind option and the difference in cost over a small print run is rarely worth arguing about.

For wedding photos, family portraits, gallery-quality work, anything you genuinely care about — sampling is worth the small amount of extra time it takes. For everyday photo prints — pricing-list visuals, event records, business documentation — the printer’s default stock at their default weight is usually fine.

PVC banners and vinyl

Outdoor PVC banner vinyl is measured in gsm just like paper, but the numbers and the use case are very different. The everyday standard for outdoor banners in South Africa is 510gsm. Lighter options exist (440gsm is common) and heavier options exist (610gsm and up), but 510gsm has become the default for a reason — it’s strong enough for outdoor use, thin enough to print well, and the cost difference between it and the cheaper alternatives is small enough that most printers just stock 510gsm.

Going lighter than 440gsm starts to compromise outdoor durability and gives the banner a flimsy feel. Going much heavier than 510gsm rarely produces a meaningful improvement for the price — it’s more weight, more cost, harder to handle, and the banner doesn’t last meaningfully longer in the SA sun.

Mesh PVC (perforated for wind release) is different. Common weights are around 270gsm because the perforations require less material. Mesh is essential for any large outdoor banner in Cape Town because of the southeaster, and useful in other coastal and high-wind sites.

Cast vinyl (the premium vehicle wrap and signage material) is sold differently — usually by micron thickness rather than gsm. 3M, Avery and ORAFOL cast vinyls run around 50–60 microns and are designed for compound curves and long outdoor life. Calendered vinyl, the cheaper option, runs thicker (80–100 microns) but doesn’t conform to curves and lasts a fraction of the time.

The cast vinyl trap is paying for premium when you don’t need it. A short-term promotional decal on a flat panel doesn’t need a 7-year cast vinyl. Calendered will do the job for a fraction of the cost. Save the cast vinyl money for full vehicle wraps, long-term signage and anything on curved surfaces.

Canvas prints

Canvas weights run heavier than paper because canvas is doing structural work — it needs to stretch over a frame without tearing or sagging. Common weights for printable canvas in SA are around 340–400gsm. Lighter canvases (under 300gsm) tend to be cotton-poly blends and can sag under their own weight on larger sizes. Heavier canvases (450gsm+) are usually pure cotton and hold up better long-term but cost considerably more.

The mistake customers make most often with canvas: assuming all printable canvas is the same. The coating that receives the ink varies enormously between suppliers. A bad-coated canvas at any weight will produce muddy, dull prints. A well-coated canvas at a reasonable weight produces vivid, gallery-quality images.

Same advice as photo paper: ask for a sample print of the supplier’s canvas stock before committing to a large run. Different printers carry different canvases, and the only way to know if you like a particular canvas is to see it printed with your image, not a generic test pattern.

Specialty stocks and customer-supplied paper

Recycled and eco stocks

Recycled paper options are more available in South Africa than they used to be, particularly in the Cape Town design market where eco credentials matter to a lot of brands. Expect to pay 10–25% more than equivalent virgin paper. Most recycled stocks are uncoated, which suits a natural-feel aesthetic but limits colour vibrancy for photo-heavy work. FSC-certified options are available from larger suppliers if certification matters for tender or corporate-policy reasons.

Textured and specialty stocks

Linen finish, felt finish, kraft, cotton-rag and other textured stocks have their place — usually for high-end branding, invitations, packaging samples and design-studio work. They tend to be more expensive, harder to source, and not stocked by most volume printers. If a customer specifically wants a textured stock, the supplier needs to know upfront because they may need to order it in for the job.

Can I supply my own paper?

Most South African printers won’t accept customer-supplied paper, and there’s a sensible reason. Printers calibrate their machines for the specific stocks they run. An unfamiliar paper might not feed properly, might absorb ink differently, might require a printer profile they don’t have. If the job fails or needs a reprint, who pays for the materials and time? It’s a liability problem more than a technical one. The exceptions are some specialty and boutique printers who’ll work with customer stocks on a case-by-case basis, usually for premium pricing and with the understanding that the customer accepts the risk.