Two posters on a screen can look exactly alike. Same image, same size, same white background in the product photo. One costs 149 kronor, the other 399. The difference isn’t visible until the package is opened – and sometimes not until three years later, when one has yellowed at the edges and the other’s blue tones have shifted toward gray. This is a buying guide for anyone who wants to assess a poster before the money leaves their card, without having to take the seller’s word for it.
Quick facts: Paper in the 230–280 g/m² range is considered museum quality for art prints in the industry. Professional pigment inks score 6–8 on the Blue Wool scale, which corresponds to 50 to over 200 years of display life under normal conditions. Age-resistant paper is measured according to ISO 9706, which sets requirements for pH value, alkaline reserve, kappa number, and tear strength – in Sweden, it is tested by the research institute RISE, among others.
Paper weight is the first thing you can measure – and the only figure that is immediately visible
Paper weight is given in g/m² and describes how much a square meter of paper weighs. It says nothing about archival quality, but it determines how the sheet behaves physically. Below 170 g/m², the paper is so flexible that it ripples in the frame as soon as the humidity changes, which happens every time the radiator is switched on in October. The result is a visible wave across the middle of the image.
Between 170 and 200 g/m² works for smaller sizes such as 21x30 cm and 30x40 cm, where the sheet has a short span. For 50x70 cm and larger, you should require at least 200 g/m², and for 70x100 cm or 100x140 cm, 230 g/m² or more is what keeps the poster hanging flat without a mat. What the industry calls museum quality falls within the 230 to 280 g/m² range.
Be aware that paper weight is sometimes confused with thickness. A bulky, heavy paper can weigh less than a thin, dense cotton paper. If the store lists both paper weight and caliper in micrometers, you have more to go on, but paper weight alone is enough for an initial filter.
Pigment ink or dye ink – the difference that determines whether the image lasts ten years
This is the single most important technical question, and it is almost never mentioned in product descriptions. Dye inks are dissolved dye molecules that penetrate the fibers. They initially produce highly saturated colors and are inexpensive, but the molecules break down under ultraviolet radiation. A poster printed with dye inks and hung on a wall with indirect daylight can start to lose contrast after just two to five years.
Pigment inks, on the other hand, consist of solid particles encapsulated in a binder that sits on top of the surface. The particles are essentially finely ground minerals and are incomparably more lightfast. Combined with archival paper, their durability is typically stated as over a hundred years.
The term giclée is used for high-resolution inkjet printing with pigment inks on cotton- or cellulose-based art paper. Professional machines work at 2400 dpi or more, with eight to twelve separate ink channels instead of the four in an office printer. More channels mean smoother transitions in skin tones, skies, and grayscales – which is especially noticeable in black-and-white posters, where the entire effect lies in the grayscale.
"A cheap print doesn't cost less. It just costs you later, when you have to buy the same design again."
The Blue Wool scale and ASTM – the two measures that actually matter
Lightfastness is not a matter of opinion; it is measured. The internationally established Blue Wool scale ranges from 1 to 8, with each step roughly corresponding to a doubling of the time until noticeable fading. A material rated at level 1 visibly fades within a few weeks in strong light. Professional pigment inks rate 6 to 8, which in practice means a display life of 50 to over 200 years in normal indoor lighting.
Alongside this, there is the American ASTM standard for printing inks, which rates lightfastness from I to V, with I being the highest. If a supplier lists any of these ratings, you have a comparable figure to go by. If it only says the colors are durable, you have nothing at all.
Two things affect the result more than anything else after purchase. Direct sunlight dramatically shortens the lifespan, regardless of ink, while glass or an acrylic sheet with a UV filter can multiply it several times over. Never hang a valuable print on a south-facing wall without protection, however tempting the light may be.
Tip: Do an edge test when the package arrives. Gently bend a corner a few millimeters. High-cotton-content archival paper springs back without cracking on the surface, while cheap coated paper develops a white crease that never goes away. The test takes three seconds and can be done within the return period.
Acid-free, lignin-free, and ISO 9706 – what the certifications actually promise
Lignin is the substance that binds wood fibers together. It’s also why a newspaper turns yellow after a couple of weeks on a windowsill. Lignin-free paper has had the lignin removed during pulp production and therefore doesn’t yellow in the same way.
Acid-free means that the paper has a neutral to slightly alkaline pH. Truly age-resistant papers also have an alkaline reserve, a built-in buffer of calcium carbonate that neutralizes the acids the paper inevitably encounters over time through air pollution.
The standard that brings all of this together is called ISO 9706 and sets requirements for pH, alkaline reserve, kappa number and tear strength. Paper that meets it should last for several hundred years under normal conditions. The stricter ISO 11108 applies to archival paper. If you’d like to read the requirements in the original, they are described by RISE, which conducts the testing in Sweden, and Swedish government requirements for permanent paper are set out in the National Archives’ regulations RA-FS 2006:4.
FSC certification is a different matter altogether and is often confused with the previous points. It tells you something about the forest management behind the pulp, not how long the sheet will last. Both are reasonable things to ask about, but for different reasons. You can read more about this in our guide to eco-friendly posters and sustainable wall art.
Resolution and color space – why the same file won’t work for every format
A digital image file contains a fixed amount of information. Printing cannot create details that aren’t in the original, no matter how good the machine is. The rule of thumb in the printing industry is 300 dots per inch at the final size, which for a 70x100 cm format means a file of roughly 8300 by 11800 pixels. Many images sold in large formats never come close.
Photographic and painterly images often do just fine, since soft transitions can handle interpolation. Sharp lines, typography and fine halftone patterns cannot. A thin line that should be razor-sharp turns gray and fuzzy as soon as the resolution falls short, and that’s when you regret choosing the largest format.
The color gamut is the other half of the same question. Screens display color additively in the sRGB color space, while printing works subtractively. The brightest colors on screen, especially vivid cyan and intense orange, simply can’t be reproduced on paper. A good printer converts using what’s known as perceptual rendering, which gently compresses the entire range instead of clipping the highlights. The effect is most noticeable in saturated designs, while muted earth tones and grayscale are barely affected. So expect a colorful design to look a little more subdued on the wall than on screen - that’s physics, not carelessness.
The finish: matte, semi-matte, or glossy - and why the light in the room makes all the difference
Matte paper diffuses light and produces no reflections. It’s forgiving in rooms with windows opposite the wall and suits graphic designs and large areas of color. The trade-off is that blacks look slightly lighter and the deepest tones lose a little depth.
A semi-matte or satin finish is the compromise that works in most homes. It retains deeper blacks and slightly more shine in saturated colors without reflecting lamps. It’s usually the right choice for photographic designs, as is clear from photographic art, where the grayscale does all the work.
A glossy surface gives maximum depth and color saturation, but in practice it’s a mirror. In a room with ceiling lights or windows opposite, you’ll see yourself more often than the design. Avoid it if the wall is opposite a light source. If you want to compare paper prints with other materials, you can find a more detailed discussion in our guide to posters or canvas.
Five warning signs to look for when comparing posters online
The first is a lack of numbers. A store that’s proud of its paper specifies its weight in grams per square meter in the product details. If it only says “high-quality paper,” it’s often 150 g/m².
The second is product images consisting exclusively of rendered room scenes, without a single close-up of the print. You can’t judge a surface you never get to see.
The third is very high-resolution designs sold in sizes up to 100x140 cm without the store specifying the file’s original resolution. A scanned artwork from a museum database might look excellent at 50x70 but soft and fuzzy at a large size.
The fourth is promises of a hundred years of durability without mentioning the type of ink. That promise applies to pigment ink on archival paper, and nothing else.
The fifth is extremely low shipping costs for large formats. A 70x100 cm print should be delivered in a tube or flat packaging with cardboard protection. If it arrives folded in a standard envelope, you’ll have a visible crease forever, no matter how good the paper was.
Once you’ve got the basics down, the rest of the purchase becomes easier. Choosing the right size for your wall is the next question, and we’ve covered it in our guide to how to choose the right poster size.
Frequently asked questions about paper quality and printing
In summary, three details are enough to tell a good print from a bad one: the paper weight, the type of ink, and whether the paper is acid-free and lignin-free. If the store lists all three in the product details, there’s a good chance the rest has been thought through too. Among our posters and artworks by famous artists, you’ll find the designs, and our range of frames offers the protection that lets them age at their own pace.