Paper weight is usually specified in grams per square metre (gsm) and thickness in millimeters (mm) – and there’s no accurate correlation between these measurements. Some manufacturers use gsm, while others use mm.
Heavier papers have a more substantial and tactile feel that implies higher quality, while lighter papers are more easily bound into books. At least 260 gsm is recommended for A3+ prints and 310 gsm for A2 prints.
The ideal paper weight for books that are printed double-sided is between 170 and 230 gsm, depending on page size. Watch out for “show through” where the image is visible on the reverse side of the sheet.
Many consumer-level printers can’t handle thicker, heavier papers and most photo printers provide alternative single-sheet slots for use when printing on ‘fine art’ media. Check your printer’s specifications to find out its limitations.
The type of printer you’re using determines whether you use dye or pigment inks. Printers that use dye-based inks deliver the maximum amount of detail and boldest colours on glossy and lustre (semi-gloss) papers. Dye-based prints are also more robust when handled because the dyes are absorbed into the paper’s surface coating.
Pigment ink printers work best with matte and lightly-textured papers but they can also be used with heavier ‘fine art’ media. Because pigment inks lie on top of the coating layer, these papers have enough surface roughening to hold the particles of pigment in place. Nevertheless, prints require careful handling to prevent the pigments from flaking. Spraying the surface of the print with a fine coat of preservation lacquer is recommended.