The reference
index of paper.
Every paper grade, mill, brand and certification — catalogued, cross-referenced and assigned a permanent WPI ID. Free, open, and obsessively maintained by people who love a good watermark.
cotton rag, 120 gsm
A long-fibre cotton rag stock, mould-made on a cylinder machine with a four-sided deckle edge. Internally sized with AKD. Traditionally used for intaglio and letterpress editions — takes damp well, prints crisp, ages slow.
Paper
has a
shelf.
A live sample from A to Z.
Look up any
paper,
anywhere.
Or start by category — we've organized every known paper grade into twelve families and sub-indexed by use, furnish, finish and region.
A sample
of the index.
Each entry is a permanent record — cross-referenced with the mills that produce it, the brands that sell it under a trade name, and the use-cases it serves. Click any row to open the full specimen sheet.
Papers of note.
Not just a catalogue. We write long-form articles about the papers that shaped letters, commerce and culture — from the fibre up. Part history, part spec-sheet.
Why bible paper is 30 gsm and still stops a bullet of ink.
The thinnest commercial paper in wide production is opaque, strong and almost tissue-light. It's not magic — it's titanium dioxide, long fibres, and a very confident calender. A short history of India paper.
Read the article →The right paper for a wedding invitation — by weight, finish and fold.
Why 300 gsm cotton folds better than 350 gsm coated, and when to spec a duplex.
Read →Reading a mill datasheet: bulk, caliper, opacity, smoothness, and whiteness explained.
Every number on that spec sheet, what it measures, and why buyers fight over it.
Read →One sheet,
five questions.
What's the fibre? How is it held together? What's on its surface? How flat is it made? And how white is white? Every entry in the index answers those five questions — the same way, in the same order, every time.
That's why a WPI ID is useful: it pins one specific answer-set to one specific grade, forever. Mills change, brand names shift, but WPI-g-000342 is always a 120 gsm mould-made cotton rag with a pH of 7.8.
Open the glossary →Observe.
Trade catalogues, mill datasheets, ISO standards, customs codes. We read the boring stuff so you don't have to.
Normalize.
We reconcile a thousand trade names into one canonical grade with a single spec sheet and a permanent ID.
Cross-reference.
Every grade links to its mills, brands, certifications, and articles. Every mill links to every grade it runs.
Publish.
Free, open, CC-BY. No paywall, no login, no hidden “pro” tier.