Paper type is easy to say and hard to pin down. The weight — grams per square metre, gsm — tells you about mass, not necessarily about how a sheet will behave under a blade, how it will take ink, or whether it will curl the moment you set a wet brush near it. Two sheets can share a gsm and feel entirely different. A 90gsm cartridge and a 90gsm Japanese tissue are not the same thing in any practical sense. The number is a starting point.
Surface matters more than weight for most of what I do. Hot press, cold press, sized, unsized, coated, laid, wove — each of these describes something real about how the top of the sheet was finished, and the differences show up immediately when you try to cut, fold, print or glue. The notes below are organized by type, not by ranking. Nothing here is best. Everything here has a use and a failure mode.
The types, one at a time
Cartridge paper, 90–130gsm. This is the default, and like most defaults it is fine for most things. Surfaces vary but tend to be matte, lightly textured, and reasonably stable. Takes pencil, most water-based inks, and light washes without obvious drama. Cuts cleanly under a fresh blade at the lighter weights; at 130gsm you are starting to push the blade slightly harder on curves, and the edge can compress if you rush. Folds well if you score first. The failure mode is batch variation — cartridge can arrive noticeably more absorbent or stiffer than the previous order, and cheaper brands are worse for this. Worth testing a sheet before committing a print run.
Hot-press watercolour paper, 200–300gsm. The surface is smooth — pressed flat under rollers — and this makes it the best substrate I have found for tight inked line work. Detail holds. Ink sits on the surface long enough to manipulate before it sinks. At 300gsm it doesn't cockle badly under a moderate wash, and it stays flat on a light table. Too heavy and smooth for stencil cuts — it's hard to get clean lift at a fold — but as a printing and drawing surface it earns the cost. Caveat: the sizing varies between manufacturers. Some hot-press papers are so heavily sized they resist thin washes initially, requiring light passes before the surface accepts anything at all. It is worth knowing whether your paper is internally or surface-sized before you commit.
Cold-press watercolour paper, 200–300gsm. The texture — often called NOT, meaning "not hot-pressed" — is more forgiving of uneven ink application, which is both a feature and a problem. Lines spread slightly. Edges of cut forms pick up ink unevenly if you're printing over the cut. Good for looser work, collage elements, textured grounds. At the heavier weights it barely moves under water, which matters when you're gluing. Where cold-press causes trouble is in cut-paper work: the texture grabs the blade tip on directional changes. A curved cut that would be controlled on a smooth sheet becomes a negotiation.
Japanese tissue and kozo papers, approximately 12–45gsm. The lightest materials I work with regularly, and they require a different set of habits entirely. Kozo fibre is long, and this means the tear is controlled in a way that wood-pulp papers rarely are — you can use torn edges deliberately. The surface takes ink slowly and somewhat unpredictably; a pigment-heavy ink will sit, a very fluid dye-based ink will bleed. Cutting requires a fresh blade and almost no pressure — these papers cut better when you're barely dragging, not pushing. They collapse under a heavy hand. They are also difficult to glue: most PVA will wrinkle them on contact unless you are working very fast or using paste instead. Not a paper to introduce to a new process. Come to it with a settled method.
Newsprint, 45–50gsm. Useful specifically because it costs almost nothing. I use it to test cuts, layouts, ink viscosities. It is acidic and yellows relatively quickly, which matters if you're making anything that needs to last, and it tears unexpectedly across the grain if you're not paying attention. The surface is soft and slightly absorbent — solvent-based inks dry fast on it; water-based ones sink. It's not a display material. It is a practice material, and as such it is irreplaceable.
Coated stock, 100–300gsm. This covers offset printing paper and the heavier coated boards used in commercial printing — surfaces that have been clay-coated to be nearly non-absorbent. Ink sits on top and requires some drying time before anything stacks on it. It cuts with almost uncomfortable precision: the edge is extremely clean, the surface shows fingermarks, and the blade feels like it's working through plastic rather than fibre. Not a natural fit for hand processes, but useful when you want that clean-edged machine quality deliberately. The gloss surface resists most adhesives; you need to roughen it, or accept that joins will be surface-level only. Folds crack without scoring.
Tissue paper and wrapping papers, 17–30gsm. Distinct from Japanese tissue — this is the wood-pulp, low-grade, commercial product. Very soft surface, no tooth, limited wet strength. Tears without much persuasion. I include it because it layers unexpectedly well in collage work: the translucency allows colour to accumulate, and it accepts acrylic medium thinly diluted as an adhesive-and-medium in one pass. It's not a precision material. It rewards loose approach.
An honest note on variability
Almost none of the above is perfectly stable advice. Paper from the same manufacturer with the same name can shift between production runs — the sizing changes, the surface weight changes, the fibre composition changes. Suppliers reformulate. Batches labeled identically will occasionally behave differently. The most useful habit I've developed is keeping a sample of each working batch and writing on the back what it took, what it resisted, and when I bought it. A small thing, but it has saved me from an otherwise unexplained failure on more than one occasion.
Weight and surface are the two axes. Supplier is the third, quieter one that most people don't track until something goes wrong.