The Numbers That Actually Matter

Start with resolution, because everything else depends on it. A print needs a source file of around 300 DPI at the size you are buying. A 24 by 30 inch canvas therefore needs roughly 7,200 by 9,000 pixels of real image data. Sellers who upscale a small file to hit that number produce a print that looks acceptable from across the room and falls apart at arm's length. Ask what the native scan resolution is, not the output resolution.

The second number is the colour profile. Faithful reproductions are printed in a wide-gamut profile and soft-proofed against a reference image of the original. If a seller cannot say what profile they use, that is an answer in itself. For a painter working in the decades around the Second World War whose originals sit mostly in private and regional collections, the reference image is often the best available record, so its quality sets a ceiling the print cannot exceed. When comparing sellers, our guide to buying her work for a living room covers where the best source files come from.

What to Check in the Preview

Zoom to 100 percent on the product image and look for three things. Brush texture, canvas weave or paper grain, and edges that hold their shape. A low-resolution source shows smeared highlights, plastic-looking skin tones and halos along contours. Recolouring is the other common fault. Over-saturated skies and skin that has drifted toward orange usually mean someone ran the file through automatic enhancement rather than matching it to the original.

Then compare against an independent reference. Public-domain paintings are usually documented by the holding museum or archive, and that image is your ground truth for colour and composition. If the seller's version is noticeably warmer, brighter or more contrasted, the reproduction has been adjusted. This matters more with less-documented artists, where a bad scan can become the version everyone copies. The same checks apply whether you buy a framed poster or a canvas, and our comparison of the two formats explains how each handles detail differently.

Red Flags and Reasonable Assurances

Some distrust is warranted. Print-on-demand marketplaces list thousands of titles, and the person selling often has never seen the file at full size. Warning signs include product images that are watermarked or heavily compressed, no stated DPI, no return policy for print quality, and listings that use the same generic description across many artists. None of these proves a bad print, but together they shift the odds against you.

Reasonable assurances look different. A seller who names the source archive, states the native resolution, prints on demand rather than from stock, and accepts returns on quality grounds is telling you the process can bear scrutiny. Price is a weak signal in both directions. A cheap print can be faithful, and an expensive one can be an upscaled JPEG. Judge the process, not the number. For sizing choices that affect how much detail you actually see, see our guide to print sizes for smaller rooms on matching scale to wall space.