# Paper & Cardstock: research notes

Date: 2026-10-25. Scope: loose-sheet and roll paper bought by the pack: office copy and printer paper (including inkjet photo and fine-art inkjet paper), cardstock and craft paper (cover stock, construction paper, 12 x 12 in scrapbook sheets), art paper sold as sheets, pads or blocks (watercolour, mixed media, drawing, pastel), and receipt and thermal paper (direct thermal rolls, thermal sheets for portable printers, and plain or 2- and 3-ply register rolls for impact and kitchen printers; scope widened in the blind-check fixes). Not bound sketchbooks, journals, notepads or sticky notes (sibling `notebooks`), blank cards, pre-scored card blanks and envelopes (sibling `cards`), sticker and label sheets and thermal labels (sibling `labels`), tissue and wrapping paper (sibling `gift-bags`). Not foam, poster, illustration or mat board (sibling `stationery-boards`). Where a pre-scored greeting-card sheet is sold as cardstock, the register's cardstock facets apply but the product belongs to `cards`.

Quote labels: **verbatim** = the sentence in quotation marks was in text I read myself (curl plus HTML stripping, pdftotext on a downloaded PDF, or JSON from a store's product feed); **fetched excerpt** = paraphrase of a page I read; **search excerpt** = the claim came from a search-engine summary and the page itself was not read. A search-excerpt-only number does not go in category.json.

Note on method: the session's WebSearch budget ran out after the first four searches (shared across parallel agents). Every other source below was reached by fetching known URLs directly, following links inside fetched pages, Shopify `products.json` feeds, or the Internet Archive. That limited the brand coverage for office paper (Hammermill only) and meant no retail marketplace listing was read.

## Seed

Seed output (verbatim from `seed.py --category paper`):

- Example: bedsheets `weave`: "the expert split is often not the number everyone advertises. Thread count is the generic trap here. Weave is what changes how the sheet feels and sleeps."
- Persona: "A tailor, who thinks in fit, drape and what you can alter afterwards"

1. **The paper equivalent of thread count is the brightness number (92, 96, 100) on copy paper, and, close behind, the pound weight in US titles.** Brightness is what the ream advertises, but it is measured at 457 nm, inside the band where optical brighteners fluoresce, so numbers above 100 on the ISO scale are brighteners, not whiter pulp, and TAPPI and ISO figures do not convert (Wikipedia, bleaching of wood pulp; Wikipedia, optical brighteners; both verbatim). The pound weight is the bigger trap: 110 lb is 199 gsm for Hammermill's cardstock (index weight; Hammermill does not name the grade) and 298 gsm for 110 lb cover. What actually changes how a sheet behaves is the job it was made for (copy, coated inkjet, cover stock, cotton watercolour, thermal), which became split 1, and gsm, which became the weight facet. **Kept**: brightness as a low-priority annotation with a judgement; pounds as a derived conversion to gsm.
2. **A tailor notices grain first: which way the fibres run, which decides how the sheet folds, drapes round a roller and cracks.** Paper has a grain exactly like cloth. Cardstock folds cleanly with the grain and cracks against it unless scored, and long-grain card resists bending round printer rollers (Cardstock Warehouse, verbatim). "What you can alter afterwards" maps to sizing and fibre in watercolour paper: whether you can lift, scrub and rework (handprint, Paul Rubens, Arches). **Kept**: `grain_direction` (researched, high cost, annotation only), and the lift-and-scrub argument inside `fibre_content`. **Dropped**: "drape" as a facet. The closest paper property is stiffness, which caliper and gsm already carry.

## Sources and what each supports

### Regulators and standards (permanence and thermal paper)

**Commission Regulation (EU) 2016/2235, BPA in thermal paper (EUR-Lex HTML via Internet Archive; the live page returned nothing to curl)**
https://web.archive.org/web/2023/https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32016R2235
- verbatim: "Shall not be placed on the market in thermal paper in a concentration equal to or greater than 0,02 % by weight after 2 January 2020."
- verbatim: "the population at risk was the unborn children of pregnant workers and consumers exposed to BPA contained in the thermal paper they handle."
- Supports: the EU limit and date, and who it protects. Confidence high.

**ChemSafetyPro, "Regulation (EU) 2016/2235 Adds Bisphenol A (BPA) to REACH Annex XVII" (2016-12-14)**
https://www.chemsafetypro.com/Topics/Restriction/Regulation_EU_2016_2235_Bisphenol_A_BPA_ban_thermal_paper_REACH_annex_xvii.html
- verbatim: "Entry 66: Bisphenol A (CAS No 80-05-7) Shall not be placed on the market in thermal paper in a concentration equal to or greater than 0,02 % by weight after 2 January 2020."
- verbatim: "BPA is currently classified as reproductive toxicant category 1B under the EU CLP Regulation".
- Supports: second source for 0.02 percent and 2 January 2020; entry number 66. Confidence high.

**US EPA Design for the Environment, "Bisphenol A Alternatives in Thermal Paper", final report January 2014 (PDF, pdftotext)**
https://www.epa.gov/sites/default/files/2014-05/documents/bpa_final.pdf
- verbatim: "BPA is also a commonly used developer in a number of thermal paper applications, such as point-of-sale (POS) receipts."
- verbatim: "When used in thermal paper, BPA is present as "free" (i.e., discrete, non-polymerized) BPA, which is likely to be more available for exposure than BPA polymerized into a resin or plastic".
- verbatim: "No clearly safer alternatives to BPA were identified in this report – most alternatives have Moderate or High hazard designations for human health or aquatic toxicity endpoints."
- verbatim: "19 potential chemical alternatives were identified for evaluation".
- Supports: developer is the chemical that matters; BPA-free is not the same as safer. Confidence high.

**Wikipedia, Thermal paper (fetched 2026-10-25)**
https://en.wikipedia.org/wiki/Thermal_paper
- verbatim: "Four different types of imaging chemicals are used in thermally sensitive papers: leuco dyes, developers, sensitizers and stabilizers."
- verbatim: "From about 2013 bisphenol S (BPS), an analog of BPA that has been shown to have similar in vitro estrogenic activity to BPA, [...] has been used in thermal paper coatings."
- verbatim: "Newer formulations are available which use either urea -based compounds or vitamin C , and are "phenol free". [...] They can have comparable or even improved print quality, but cost more."
- verbatim: "An unintended heat source, such as a coffee cup, can discolour the paper and obscure any printing."
- verbatim (for the mechanism): coating "formulated to change color locally when exposed to heat"; used in "cash registers , credit card terminals and small, lightweight portable printers".
- Supports: BPS as the common replacement, phenol-free options, the mechanism. The article carries citation-needed banners; I used it only where EPA or EUR-Lex says the same thing or for the mechanism. Confidence medium.

**Ellen McCrady, "The ANSI/NISO Z39.48 Standard and Other Standards", Abbey Publications 1998, on CoOL (curl, gzip)**
https://cool.culturalheritage.org/byorg/abbey/napp/std.html
- verbatim table for ANSI/NISO Z39.48-1992: "pH: 7.5-10.0" (uncoated); "Alkaline reserve (CaCO 3 equivalent): 2% minimum"; "Tear index: 5.25 mNm 2 /g" (uncoated), "3.50" (coated); "1% lignin maximum (Kappa number no greater than 7)".
- verbatim: ISO 9706 "Its provisions are very similar to those of ANSI/NISO Z39.48-1992, but its requirements for tear resistance and maximum Kappa number ("resistance to oxidation") are slightly different (5, rather than 7)."
- verbatim: "D 3458 also has requirements for brightness, opacity, fluorescence" (ASTM permanent copy papers).
- Supports: the two permanence standards and their thresholds. Confidence high.

**Library of Congress, Ask a Librarian, "What is permanent paper?" (updated 2025-03-03)**
https://ask.loc.gov/preservation/faq/337512
- verbatim: "Permanent paper is defined by [...] ANSI/NISO Z39.48-1992 (R2009) [...] which specifies a 2% minimum alkaline reserve, less than 1% lignin, good tear resistance, and a pH range between 7.5 to 10.0."
- Supports: second source for pH 7.5 to 10, 2 percent reserve, under 1 percent lignin. Confidence high.

**Wikipedia, Acid-free paper**
https://en.wikipedia.org/wiki/Acid-free_paper
- verbatim: "Much commercially produced paper is acid-free but this is largely the result of a shift from kaolin clay to precipitated calcium carbonate (PCC) as the main filler material in the pulp."
- verbatim: "In some quarters, slightly-acidic paper having a pH between 6 and 7 is often also considered "acid-free"."
- verbatim: "Manufacturers of acid-free paper can indicate the compliance of their product with the test requirements of the ISO 9706 or ANSI Z39.48-1992 standards using a circled infinity symbol".
- verbatim: "The international standard for "permanent" paper is ISO 9706 and for "archival" paper, the standard is ISO 11108."
- Supports: "acid-free" alone says little; the infinity mark; ISO 11108. Confidence medium (Wikipedia, but consistent with McCrady).

### Weight, grades and thickness

**mcgpaper, "How To Make - Paper weights and conversion tables"**
https://mcgpaper.com/pages/how-to-make-paper-weights-and-conversion-tables
- verbatim: "Basis Weight: Weight in lbs of 500 sheets at standard size." Basis sizes: "Bond / Ledger / Rag 17" × 22"", "Offset / Text / Coated 25" × 38"", "Cover Stock 20" × 26"".
- verbatim table rows (Bond, Text, Cover, Index, Points, GSM): "20 50 28 42 3.8 75.2"; "24 60 33 50 4.8 90.3"; "47 120 65 97 8.0 176.8"; "65 165 90 135 10.0 244.5"; "82 208 114 170 14.0 308.5". "* Caliper may vary by ±5–7% depending on manufacturing."
- verbatim: "80 gsm / 21 lb: Standard copy paper weight."
- Supports: basis sizes, conversion, points versus gsm. Confidence high.

**Clear Print, "GSM Paper Weight Chart" (2014)**
https://www.clearprint.com/gsm-paper-weight-chart/
- verbatim: "20lb Bond/Writing/Ledger 75 gsm", "24lb Bond 90 gsm", "32lb Bond 120 gsm", "50lb Book/Text/Offset 75 gsm", "110lb Index 200 gsm", "65lb Cover 175 gsm", "80lb Cover 215 gsm", "100lb Cover 275 gsm", "130lb Cover 350 gsm".
- verbatim: "Bond, Writing, Ledger, Offset, Bristol and Index stocks are all UNCOATED."
- Supports: second chart; 110 lb index is about 200 gsm. Confidence high.

**Cardstock Warehouse, "Paper 101 - Paper Weight Guide"**
https://cardstock-warehouse.com/pages/cardstock-paper-basis-weight-chart
- verbatim: "Why is 80 lb. text paper thinner than 65 lb. cover? [...] 80 lb. text is about 118 gsm, while 65 lb. cover is about 176 gsm."
- verbatim: "65 lb. cover 176 gsm 80 lb. cover 216 gsm 100 lb. cover 270 gsm 110 lb. cover 298 gsm 130 lb. cover 352 gsm".
- verbatim: basis sizes "Book or Text 25 x 38 inches Index 25.5 x 30.5 inches Bristol 22.5 x 28.5 inches Cover 20 x 26 inches".
- verbatim: "What most people call "cardstock" is technically cover paper."
- verbatim: "Thickness, or caliper, is measured with a micrometer in points, where 1 pt. = 1/1000 of an inch. Weight is a good guide to thickness, but two papers of the same weight can differ. It depends on the fibers used and how much the paper is pressed smooth during manufacturing, a process called calendering ."
- Supports: grade-dependent pounds, cover = cardstock, caliper. Confidence high.

**Wikipedia, Paper; Card stock; Copy paper ("Special fine paper"); Bond paper; Paper size**
https://en.wikipedia.org/wiki/Paper, https://en.wikipedia.org/wiki/Card_stock, https://en.wikipedia.org/wiki/Copy_paper, https://en.wikipedia.org/wiki/Bond_paper, https://en.wikipedia.org/wiki/Paper_size
- Paper, verbatim: "Printing paper is generally between 60 gsm and 120 gsm. Anything heavier than 160 gsm is considered card." and "Sheets are usually cut "long-grain", i.e., with the grain parallel to the sheet's longer dimension." and handmade papers are "characterized by lack of grain direction".
- Card stock, verbatim: "The weight of cardstock ranges from 50# to 110# (about 135 to 300 g/m 2 )." and "a 10 pt. card is 0.010 in (0.254 mm) thick (corresponding to a weight of about 250 g/m 2 )" and "a sheet of 65# card stock is thicker and heavier than a sheet of 80# newsprint."
- Copy paper, verbatim: "The basis weight is 70-90 g/m 2 (approximately 18-24 lb) and ISO brightness 80-96%. It is made of 90–100% virgin chemical pulp or 100% deinked pulp".
- Bond paper, verbatim: "The most common weights are 60 g/m 2 (16 lb), 75 g/m 2 (20 lb) and 90 g/m 2 (24 lb)."
- Paper size, verbatim: Letter "8.5 in × 11 in; 216 mm × 279 mm"; A4 "210 mm × 297 mm"; North American sizes "governed by the ANSI".
- Supports: weight bands, cardstock range, caliper anchor, sheet sizes. Confidence medium to high.

### Printers

**Brother HL-L2350DW (mono laser) product page**
https://www.brother-usa.com/products/hll2350dw
- verbatim: "Sheet Weight - Paper Tray (Min/Max)‡ 16-43 lbs. (bond)"; "Sheet Weight Manual Feed 16-61 lbs. (bond)"; "The manual feed slot offers flexible paper handling for a variety of papers and sizes, such as card stock".
- Supports: printers state limits in pounds bond; tray versus manual feed. Single printer; used only as an example.

**Brother MFC-J4335DW (inkjet) product page**
https://www.brother-usa.com/products/mfcj4335dw
- verbatim: "Sheet Weight - Paper Tray (Min/Max)‡ 17 - 58 lbs. (bond)"; "Sheet Weight Manual Feed 17-79 lbs (bond)".
- Supports: same, for an inkjet. Single printer; example only.

**Cardstock Warehouse, "Paper 101 - Printing On Cardstock" and "Scoring, Folding and Paper Grain"**
https://cardstock-warehouse.com/pages/cardstock-paper-101-printing
https://cardstock-warehouse.com/pages/cardstock-paper-101-scoring-and-folding
- verbatim: "The paper grain is the direction in which most of the paper fibers run. Grain typically runs with the length of a rectangular sheet, which is known as long grain".
- verbatim: "a long-grain paper will be more resistant to bending around the roller than a short-grain paper. So a short-grain paper may bend just enough to allow it to feed, while a long-grain paper may not feed or jam."
- verbatim: inkjet "may not work, or work as well, on certain coated and reflective papers where ink is not readily absorbed and can easily smear and smudge."
- verbatim: laser "allows for printing on some surfaces that inkjet cannot print on such as metallic, pearlescent, and reflective paper."
- verbatim: scoring "Prevents the paper from "cracking" along the fold line".
- verbatim: "be sure your printer can handle the GSM weight of your cardstock."
- Supports: grain, scoring, printer feeding, inkjet versus laser surfaces. Confidence high.

**mcgpaper product feed (`products.json`, product FAQ text)**
https://mcgpaper.com/products.json
- verbatim (Photo Gloss Inkjet Card Stock): "Is this compatible with laser printers? No. This coating is specifically engineered for inkjet ink absorption . Laser heat can damage the specialized gloss surface."
- verbatim (Pearl Essence Gloss Photo Paper): "Because of the specialized microporous coating, it is not recommended for Laser Printers , as the high heat can damage the surface coating."
- verbatim (Satin Textured Photo Card Stock): "Using it in a laser printer may result in poor image quality or damage to the printer fuser".
- verbatim: pre-scored cards fold "without cracking the paper fibers".
- Supports: inkjet-coated sheets are inkjet-only; compatibility sits in FAQ text, not a field. Confidence high.

**Wikipedia, Laser printing**
https://en.wikipedia.org/wiki/Laser_printing
- verbatim: "Toner is fused onto paper with heat and pressure."
- Supports: mechanism. Confidence high.

**Wikipedia, Inkjet paper**
https://en.wikipedia.org/wiki/Inkjet_paper
- verbatim: "Many general-purpose office papers of weights around 21 to 27 lb (80–100 g/m 2 ) have been reformulated to work equally well with both inkjet and laser printers ."
- verbatim: "Double-sided inkjet printing is usually not possible with inexpensive low-weight copy paper because of bleed-through".
- verbatim: "For maximum longevity, the paper substrate should be lignin free or cotton-based, or a combination of the two, pH neutral and contain no optical brightening agents".
- verbatim: "glossy papers give the highest color density (or D max ), and therefore the widest color gamut"; "Black density and gamut of matte papers is normally less than for gloss or luster papers".
- verbatim: "No official paper industry standard defines glossy, semi-matte, etcetera".
- verbatim: fine art inkjet papers "are usually made of rag pulp (100% cotton being the most common)".
- Supports: multipurpose paper, finish trade-offs, brighteners and longevity, fine-art inkjet counts as printer paper. Confidence medium.

### Brightness and brighteners

**Wikipedia, Bleaching of wood pulp, section "Paper brightness"**
https://en.wikipedia.org/wiki/Bleaching_of_wood_pulp
- verbatim: "In the US, the TAPPI T 452 or T 525 standards are used. The international community uses ISO standards." Table: "TAPPI brightness ISO brightness 84 88 92 104 96 108 97 ≥109".
- verbatim: "there is no simple way to convert between the two systems because the test methods are so different."
- verbatim: "The ISO rating is higher and can be over 100. This is because contemporary white paper incorporates fluorescent whitening agents (FWA)."
- verbatim: "Writing and printer paper would typically be as bright as 104 ISO."

**Wikipedia, Optical brightener**
https://en.wikipedia.org/wiki/Optical_brightener
- verbatim: "Paper brightness is typically measured at 457 nm, well within the fluorescent activity range of brighteners."
- verbatim: "The stilbene derivatives are subject to fading upon prolonged exposure to UV".

**Hammermill store product feed (`products.json`)**
https://www.hammermill.com/products.json
- verbatim titles: "Copy Plus Printer Paper, 20lb, 92 Bright", "Premium Color Copy, 100 Bright", "Premium Cardstock, White, 110lb, GSM (199)", "Opaque Colors, 65lb. Cover", "Great White® 30% Recycled Paper, 20 lb".
- verbatim options: "Basis Weight ['28 lb.', '32 lb']", "Sheet Size ['Letter (8.5 x 11)', 'Legal (8.5 x 14)', 'Ledger (11 x 17)', ...]", "Pack Size ['1 Ream (500 Sheets)', ...]".
- verbatim body: Premium Laser Print "works in all laser and color printers"; Color Copy Cover "ability to withstand heat and heavy toner application".
- Supports: which fields an office-paper brand lists (pound weight, brightness, sheet size, pack) and that the title carries them; 110 lb cardstock at 199 gsm. Confidence high for this brand.

### Art paper

**handprint.com (Bruce MacEvoy), "watercolor papers" pages 1 to 3**
https://www.handprint.com/HP/WCL/paper1.html (and paper2, paper3)
- verbatim weight table (pounds/ream for 22 x 30 in only, then gsm): "light "90" (87) 185 . "90" (94) 200 . 130 280 medium 140 300 . 190 400 heavy 260 550 . 280 600 board 300 640".
- verbatim: the ream measures "will be useful to distinguish between sheets from a single manufacturer, not to compare sheets between different manufactuerers. For that purpose, learn to think in terms of the metric weights".
- verbatim: "Watercolor papers are supplied in three types of finish or surface texture: rough, cold pressed, and hot pressed."
- verbatim: cold pressed "(in the UK called " NOT " paper, meaning "not hot pressed")" gives "a subdued texture that is relatively easy to use, can tolerate a certain amount of corrections or lifting, and is congenial to almost any style of painting."
- verbatim: hot pressed shows "a high degree of brush detail and tend to show pigment color more brightly [...] the drawback is that the lack of absorption tends to produce uneven and blotchy washes".
- verbatim: rough "sheets are usually the most absorbent, and therefore produce the smoothest washes".
- verbatim: "papers labeled "rough" in one brand line may be equivalent to a "cold pressed" in another line."
- verbatim: "Cotton cellulose is up to 10 times stronger than wood cellulose and naturally lignin free and acid free. [...] wood pulp ("alpha cellulose") papers should generally be avoided for archival or museum quality artwork."
- verbatim: archival criteria include "contain no optical brighteners".
- verbatim: "The label "100% cotton" by itself is no assurance either way, as recycled fabrics may be harshly bleached".
- verbatim: blocks "fairly well resist cockling or warping when wet, at least in the 300 GSM weight."
- verbatim: "In machinemade and to a lesser degree in some moldmade papers, the grain runs the length of the web".
- Supports: finishes, fibre, weight conversion, grain. Confidence high (the most detailed enthusiast reference on the subject, though last revised years ago).

**Arches, ARCHES Aquarelle product page**
https://arches-papers.com/arches-range-of-papers/watercolor-and-wet-techniques/arches-aquarelle/
- verbatim: "Its 100 % long cotton fibre composition"; "gelatin sizing to the core preserves the lustre and transparency of the colours whilst preventing paints from penetrating into the paper."
- verbatim: "With alkaline reserve , acid-free, no optical brightening agents (permanent in accordance with ISO 9706)".
- verbatim: "185, 300, 356, 640 and 850 gsm".
- verbatim spec table columns: "Grammage Texture Colour Format (cm) Size Imperial (inch) Edges No. of sheets Product code"; rows "185 gsm 90 lb Cold Pressed Natural white 56 x 76 cm 22 in x 30 in 4 deckle edges 25", "300 gsm 140 lb Rough Natural white 56 x 76 cm 22 in x 30 in".
- Supports: what a leading art-paper maker lists; 140 lb = 300 gsm; ISO 9706 in practice. Confidence high.

**Paul Rubens Shop, "100% Cotton Watercolor Paper: When It Matters and When It Does Not" (2026) and "Watercolor Paper Texture" (2026-07-23)**
https://www.paulrubensshop.com/blogs/knowledge/watercolor-paper-complete-guide
https://www.paulrubensshop.com/blogs/knowledge/watercolor-paper-texture
- verbatim: "Use 300 gsm / 140 lb as the default weight unless you already know you need heavier paper."
- verbatim: cotton "is less necessary for dry sketching, color notes, classroom drills, or very light washes."
- verbatim table: cotton "Stronger surface, better for scrubbing and lifting"; cellulose "More likely to pill or tear when overworked"; price "Higher cost per sheet / Lower cost per sheet".
- verbatim: "A cold press surface on thin cellulose paper can still buckle, pill, or dull color."
- Supports: cotton versus wood pulp, 300 gsm default. A brand's own guide, so I lean on it only where handprint or Edinburgh agree. Confidence medium.

**Edinburgh Art Workshop, "Finding the Right Paper" (Diana Bechmann)**
https://www.edinburghartworkshop.com/articles/finding-the-right-paper
- verbatim: "Common weights for watercolour paper range from 190 gsm to 638 gsm. Heavier paper (300 gsm and above) is less likely to buckle or warp when wet".
- verbatim: "If you're using lighter watercolor paper (less than 300 gsm), consider stretching it before painting."
- verbatim: "Cotton papers are generally higher quality, offering superior absorbency and durability, while wood pulp papers are more affordable and suitable for practice or beginners."
- Supports: second source for 300 gsm and cotton versus wood pulp. Confidence medium.

**Wikipedia, Watercolor paper**
https://en.wikipedia.org/wiki/Watercolor_paper
- verbatim: "Watercolor paper may be hot-pressed (smooth), cold-pressed (textured), or rough." "Paper traditionally comes in either 90, 140, or 300 lb weights."
- verbatim: Whatman "used gelatin as a sizing that created a protective coating that reduced damage to the paper by repeated wetting, drying and reworking."
- Supports: sizing explained; the 90/140/300 lb ladder. Confidence medium.

**Cardstock Warehouse, "Glossary of Terms"**
https://cardstock-warehouse.com/pages/paper-101-glossary-of-terms
- verbatim: "Acid-Free - paper that has a netural pH of 7.0 or more"; "Calendering - a process used in paper making that presses large sheets of paper through rollers to make it smoother."; "Coated Paper-C1S, C2S"; "Construction Paper - low-cost paper made with ground wood".
- Supports: vocabulary; acid-free threshold at pH 7 (against Wikipedia's 6 to 7 note). Confidence medium.

**Wikipedia, Construction paper**
- verbatim: "the colours given by synthetic dyes tend to fade over short periods of time, an effect often seen in construction paper". Kept in notes only.

### Added after the blind check (2026-10-25)

All read with curl and HTML stripping, Shopify `products.json`, or pdftotext. WebSearch was unavailable (session budget used up), so every URL was fetched directly.

**ECHA news release ECHA/NR/20/22, 18 June 2020 (Internet Archive; live page 403 to the checker)**
https://web.archive.org/web/2021/https://echa.europa.eu/-/bisphenol-s-has-replaced-bisphenol-a-in-thermal-paper
- verbatim: "By 2022, 61 % of all thermal paper in the EU is forecast to be based on bisphenol S (BPS)."
- verbatim: "According to the survey, BPA-based thermal paper still had a 29 % market share in 2019 in the EU."
- verbatim: "Belgian authorities are currently evaluating whether the use of BPS poses a risk to human health or the environment." and "Belgium made a proposal in 2019 to harmonise the classification and labelling of the substance as toxic to reproduction."
- Supports: BPS share; BPS under separate evaluation in 2020. Confidence high for 2020. I could not check, without search, whether any BPS restriction for thermal paper is in force on 2026-10-25, so the register says only "under separate EU evaluation in 2020".

**ECHA report "The use of bisphenol A and its alternatives in thermal paper in the EU during 2014 - 2022", ECHA-20-R-07-EN, June 2020 (PDF via Internet Archive, pdftotext)**
https://web.archive.org/web/2021id_/https://echa.europa.eu/documents/10162/2564887/bpa_thermal_paper_report_2020_en.pdf/59eca269-c788-7942-5c17-3bd822d9cba0
- verbatim: "In 2022, the volume of BPS-based thermal paper placed on the EU market is estimated to be 307 kilotonnes (61 % of total)".
- verbatim: "the overall share of BPA-based thermal paper placed on the EU market in 2019 was still 29 %, compared with 39 % for BPS and 32 % for other developers."
- Supports: second document for 61% and 29%. Both documents come from one ECHA survey, so the two "sources" are one body's report and its release; logged as such.

**Epson OmniLink TM-T88VI (thermal) product page**
https://epson.com/For-Work/Printers/POS/OmniLink-TM-T88VI-Thermal-Receipt-Printer/p/C31CE94061
- verbatim: "Media Dimensions: 80mm: 79.5 ± 0.5 (W) x 83mm diameter (3.13" ± 0.02” x 3.27") 58mm: 57.5 ± 0.5 (W) x 83mm diameter".

**Citizen CT-E351 product page**
https://www.citizen-systems.com/us/printer/pos/ct-e351
- verbatim: "59 - 80 mm (+/- 0.5 mm)" (media width), "Roll Size (max), Core Size: 83 mm outside diameter", "Paper width: Variable paper width – 58 and 80 mm".
- Supports with Epson: a roll must match the printer's width and fit its maximum diameter (about 58 or 80 mm, up to 83 mm). Confidence high.

**Epson TM-U220 (impact) product page**
https://epson.com/For-Work/Printers/POS/TM-U220-Impact-Receipt-Printer/p/C31C514653
- verbatim: "Right-side-up printing for kitchen orders"; "Accommodates paper widths of 58, 70 or 76mm"; "Ribbon cassette"; "Media Dimensions: 57.5 ± 0.5 (W) x 83mm diameter 69.5 ± 0.5 (W) x 83mm diameter 76 ± 0.5 (W) x 83mm diameter"; "Copy Capacity: One original and one copy".
- Supports: non-thermal register rolls exist, printed through a ribbon, with multi-part copies.

**POSPaper.com store feed (`products.json`, 6 pages)**
https://www.pospaper.com/products.json
- verbatim titles: "3 1/8" x 230' Thermal Paper (10 rolls) - BPA Free - FREE SHIPPING", "2 1/4" x 74' Thermal Paper (50 rolls/case) - BPA Free", "8 1/2" x 11" Heavy Thermal Paper Perforated for Brother PocketJet Printers (6 rolls/case) - OEM# LB-3663".
- Supports: US roll titles give width by length in feet, not diameter; thermal sheets for portable printers are sold.

**Till Rolls Direct (UK) store feed (`products.json`)**
https://www.tillrollsdirect.co.uk/products.json
- verbatim titles and bodies: "80 x 80 x 12.7 Core Thermal Rolls Boxed 10s", "37 x 70 x 17.5 Core Single ply A grade Rolls", "Kitchen Printer Rolls 2Ply 76mm White/Yellow Boxed 20", "Kitchen Printer Rolls 3Ply 76mm White/Pink/Yellow Boxed 20".
- Supports: UK titles give width by diameter by core in mm; 2- and 3-ply kitchen rolls at 76 mm match the TM-U220 width.

**Cardstock Warehouse weight guide, re-read**
- verbatim: "find a sturdy everyday sheet in our 80 lb. cardstock collection , or go thicker with heavyweight cardstock"; chart "70 lb. text 104 gsm 80 lb. text 118 gsm 100 lb. text 148 gsm 65 lb. cover 176 gsm 80 lb. cover 216 gsm 100 lb. cover 270 gsm".

**Hammermill feed, re-read**
- verbatim body of "Premium Cardstock, White, 110lb, GSM (199)": "our Hammermill heavyweight cardstock". The feed never names the grade; 199 gsm matches index weight (110 x 1.81).
- Brand labels disagree on "heavyweight": Hammermill uses it for 199 gsm, Cardstock Warehouse calls 216 gsm "everyday". The cardstock weight mapping therefore follows the cover-weight chart points (65 and 80 lb cover), not brand labels. Our call.

### Could not reach

Search budget exhausted after four WebSearch calls, so no search for: TAPPI's own brightness page, Domtar, Navigator, Double A or HP paper spec sheets (Navigator and Double A pages returned stubs), Neenah/Astrobrights (stub), Strathmore (product URLs 404), Red River Paper (blocked, Wayback stub), Epson and Canon printer spec pages (no weight text), Jukebox Print (blocked), Office Depot and Staples category pages (stubs). Amazon was not attempted; earlier registers record that it blocks fetches. The ISO 9706 text itself was not read; its thresholds come from McCrady and Wikipedia.

## Data points used for derived metrics

- `gsm_from_pounds`: factor = 453.592 g / (500 sheets × basis sheet area in m²). Bond 17 × 22 in → 3.76; text 25 × 38 in → 1.48; cover 20 × 26 in → 2.70; index 25.5 × 30.5 in → 1.81; watercolour 22 × 30 in → 2.13. Checks: 20 lb bond → 75.2 gsm (mcgpaper 75.2, Clear Print 75); 65 lb cover → 175.8 (Cardstock Warehouse 176, Clear Print 175); 110 lb index → 199 (Hammermill 199, Clear Print 200); 110 lb cover → 297 (Cardstock Warehouse 298); 140 lb watercolour → 298 (Arches and handprint 300); 300 lb → 639 (handprint and Arches 640).
- `fits_printer`: printer limits are given in pounds bond, so multiply by 3.76. Brother HL-L2350DW 43 lb tray → 162 gsm, 61 lb manual → 229 gsm. Brother MFC-J4335DW 58 lb tray → 218 gsm, 79 lb manual → 297 gsm. These two printers are examples, not typical values.
- `price_per_square_metre`: Letter = 0.0603 m², A4 = 0.0624 m², 22 × 30 in = 0.4258 m² (computed from the stated dimensions).

## Against the existing add-on schema

`zamana-expertise/data/schema-parts/supplies/stationery/add-ons/paper.jsonc` has `weight_gsm_lb_raw` (string), `texture` (enum smooth, textured, linen, felt, cold_press, hot_press, rough, glossy, embossed, crepe, not_applicable, unspecified), `brightness_raw` (string) and `printer_compatibility` (array of enum inkjet, laser, copier, thermal, not_printable, unspecified). `stationery-standard` is empty. `supplies-standard` gives `high_signal_markdown` and the `sizing` block (`size_stated`, `pack_count`, `dimensions`, `weight`). Field kinds follow AGENTS.md rule 4 (vertical anchor, category quality currency, hard filter, sizing). Proposals only; nothing edited.

| Register facet | Current add-on field | Proposed kind | Proposal |
|---|---|---|---|
| `paper_family` | none | hard filter | Add enum `paper_family` [printer_paper, cardstock_craft, art_paper, thermal_roll]. It routes every other field and is cheap to derive from title and product type. |
| `printer_compatibility` | `printer_compatibility` | hard filter | Keep. Drop `copier` (copy paper is the multipurpose case of laser plus inkjet; Wikipedia, copy paper is "for copying and laser printers") and fold `thermal` into `paper_family`. Keep `not_printable` for art paper. |
| `intended_medium` | none | hard filter | Add enum [watercolour_wet, drawing_dry, mixed_media] for art paper only. Titles carry it. |
| `basis_weight_gsm` | `weight_gsm_lb_raw` | category quality currency | Replace the raw string with `weight_gsm` (number) plus `weight_lb` (number) and `weight_lb_grade` (enum bond, text, cover, index, bristol, watercolour_22x30). Normalise to gsm on every row; without the grade, "110 lb" cannot be converted. Augment when missing. |
| `caliper_pt` | none | (Jev material) | Leave in markdown; brands rarely state it and gsm carries most of the signal. |
| `surface_texture` | `texture` | hard filter | Keep, but split coatings out: `texture` [hot_press_smooth, vellum_fine_tooth, cold_press, rough, linen_felt_embossed, crepe] and a separate `coating_finish` [uncoated, matte_coated, luster_satin, glossy, metallic_pearlescent]. Today glossy sits beside cold press in one enum, which mixes a coating with a texture. Texture is partly visual (AGENTS rule 1), but cold press versus hot press is stated, not seen. |
| `coating_finish` | `texture` (glossy) | hard filter | See above. |
| `fibre_content` | none | category quality currency (art paper) | Add enum [cotton_100, cotton_blend, wood_pulp, unspecified]. The single most-argued spec in watercolour. |
| `permanence` | none | (Jev material, or a hard filter for archival buyers) | AGENTS rule 5 calls certifications dead. ISO 9706 is a measured property, not a badge; I would keep a three-value enum [not_stated, acid_free_claimed, iso_9706_or_z39_48] but accept it living in markdown. |
| `optical_brighteners` | none | (Jev material) | Markdown. "No OBA" is stated on fine-art and photo papers only. |
| `brightness` | `brightness_raw` | (noise, mostly) | Keep as raw string at most; do not normalise. TAPPI and ISO do not convert, and the number is mostly a brightener reading. Candidate for removal. |
| `grain_direction` | none | (Jev material) | Markdown. Rarely stated. |
| `sheet_size` | `sizing.size_stated` | sizing | Already covered; add a normalised enum inside sizing for Letter, Legal, Ledger, A4, A3, 12x12, 22x30. |
| `roll_size` | `sizing.dimensions` | sizing / hard filter | Thermal rolls need width and diameter (and core) inside sizing. |
| `thermal_developer` | none | hard filter (safety) | Add enum [bpa, bps, phenol_free, not_stated] for thermal rolls; it is the one real health flag in the leaf (EU REACH entry 66). |

Noise in the current add-on: `brightness_raw` as a ranking field, `copier` as a printer value, and `texture: crepe` (crepe paper is a craft novelty better left to markdown).

## Branches

Rewritten after the blind check (2026-10-25); every leg the checker graded WEAK or UNSUPPORTED was removed or re-sourced.

- `paper_family` = printer paper → then ask `printer_compatibility`, `basis_weight_gsm`, `coating_finish`; `intended_medium`, `thermal_developer`, `roll_size` irrelevant. Trace: printer limits are stated per printer in pounds bond (Brother, both US pages); inkjet-coated finishes are inkjet-only (mcgpaper FAQ); weight on this branch maps to 20 to 21 lb bond as standard (Wikipedia bond paper, mcgpaper "80 gsm / 21 lb: Standard copy paper weight", Hammermill "20lb"), with 24 to 32 lb as heavier (mcgpaper, Clear Print). `brightness` removed from then_ask: it is novice_answerable false with no question, and judgement 2 says it ranks looks, not quality. `intended_medium` is defined for art paper only; thermal facets apply only to receipt paper. SUPPORTED.
- `paper_family` = cardstock and craft paper → then ask `printer_compatibility`, `basis_weight_gsm`; `intended_medium`, `thermal_developer`, `roll_size` irrelevant. Trace: "be sure your printer can handle the GSM weight of your cardstock" (Cardstock Warehouse); the printer question now asks for the model, which gives the weight limit `fits_printer` needs (Brother pages) and offers "not printing" for hand crafters; laser prints metallic and pearlescent card that inkjet smears (Cardstock Warehouse). Weight mapping on this branch: standard = 65 to 80 lb cover, 176 to 216 gsm (Cardstock Warehouse chart and "sturdy everyday sheet" at 80 lb; Clear Print 175 and 215). `grain_direction` and `caliper_pt` removed from then_ask: both are novice_answerable false and annotation-only; they stay as card annotations. SUPPORTED.
- `paper_family` = art paper → then ask `intended_medium`, `surface_texture`; `printer_compatibility`, `brightness`, `thermal_developer`, `roll_size` irrelevant. Trace: art paper in this register is for hand media; fine-art inkjet paper counts as printer paper (rule in the `paper_family` definition), so printer compatibility does not apply. Surface: handprint's three watercolour finishes and Cardstock Warehouse's vellum "fine-tooth finish" for drawing. Brightness, with the missing step stated: Arches sells whiteness as a colour choice ("Natural white" or "Bright white") and publishes no brightness number; handprint's archival criteria exclude brighteners; so the whiteness choice on art paper is carried by the colour name in the product text and by `optical_brighteners`, not by a brightness figure. SUPPORTED (chain of three stated facts).
- `paper_family` = receipt and thermal paper → then ask `roll_size`, `thermal_developer`; `printer_compatibility`, `intended_medium`, `fibre_content`, `grain_direction`, `surface_texture` irrelevant. Trace: receipt printers state paper width and maximum roll diameter (Epson TM-T88VI 79.5 or 57.5 mm by 83 mm; Citizen CT-E351 58 and 80 mm, 83 mm maximum; Epson TM-U220 impact 58, 70 or 76 mm by 83 mm), and roll listings carry the size in the title (POSPaper as width by length, Till Rolls Direct as width by diameter by core). Thermal paper prints by heat with no ink (Wikipedia) and impact rolls print through a ribbon (Epson TM-U220), so inkjet/laser compatibility, art medium, fibre, grain and surface do not apply. The developer is the regulated chemical (EUR-Lex, EPA, ECHA); it is blank for plain and multi-ply register rolls. Thermal sheets for portable printers (Wikipedia; POSPaper PocketJet sheets) use `sheet_size` instead of `roll_size`. SUPPORTED.
- `intended_medium` = watercolour and wet media or mixed media → then ask `basis_weight_gsm`, `fibre_content`. Trace: 300 gsm is the default, and lighter sheets are more likely to buckle and are often stretched or used as a block (Edinburgh, Paul Rubens, handprint on blocks); cotton matters most for washes, lifting and scrubbing and is "less necessary for dry sketching" (Paul Rubens, Edinburgh, handprint). These two facets moved here from the art-paper branch, so this branch now changes the path. Mixed media is included because the facet defines it as answering to both, and the wet half needs both facets. SUPPORTED.
- Dropped after the blind check: `intended_medium` = drawing and dry media → then ask `surface_texture`. It was WEAK by my own note (no drawing-paper reviewer saying surface is the main axis), and `surface_texture` is already asked on the art-paper branch, so the leg changed nothing.
- Dropped: `printer_compatibility` = laser → makes `coating_finish` irrelevant. Laser-rated gloss and coated papers exist (Hammermill Color Copy Cover "withstand heat and heavy toner"), so the leg is false.
- Dropped: `intended_medium` = drawing → makes `fibre_content` irrelevant. Archival drawing on cotton is real (handprint archival criteria apply to any artwork). The new structure only stops asking fibre on the dry path; it does not mark it irrelevant.

## Numbers in category.json and how many sources stand behind each

| Number | Sources |
|---|---|
| 20 lb bond = 75 gsm; 65 lb cover ≈ 176 gsm; 110 lb index ≈ 199 gsm; 110 lb cover ≈ 298 gsm | mcgpaper, Clear Print, Cardstock Warehouse, Hammermill (199), computed factors |
| Conversion factors 3.76 / 1.48 / 2.70 / 1.81 / 2.13 | Computed from basis sizes (mcgpaper, Cardstock Warehouse) and checked against both charts |
| 140 lb = 300 gsm, 300 lb = 640 gsm (watercolour) | handprint, Arches, Paul Rubens (140/300) |
| Copy paper 70 to 90 gsm; printing paper 60 to 120 gsm; over 160 gsm is card | Wikipedia copy paper; Wikipedia paper; mcgpaper "80 gsm / 21 lb: Standard copy paper"; Clear Print 20 and 24 lb bond |
| Cardstock about 135 to 300 gsm; cover 176 to 352 gsm | Wikipedia card stock; Cardstock Warehouse; Clear Print (175 to 350) |
| 300 gsm as the watercolour floor; stretch below | Edinburgh, Paul Rubens, handprint (blocks at 300 GSM) |
| Watercolour weights 185 to 640 gsm common (850 rare) | Arches (185 to 850), handprint (185 to 850), Edinburgh (190 to 638) |
| 10 pt ≈ 245 to 250 gsm; 1 pt = 0.001 in | Wikipedia card stock (250), mcgpaper (244.5), Cardstock Warehouse (pt definition) |
| ISO 9706 / Z39.48: pH 7.5 to 10, alkaline reserve 2%, lignin under 1% | McCrady (CoOL), Library of Congress |
| TAPPI 92 ≈ ISO 104; ISO over 100 from brighteners; measured at 457 nm | Wikipedia bleaching (table), Wikipedia optical brightener (457 nm); Hammermill sells at 92 |
| EU BPA limit 0.02% from 2 January 2020 | EUR-Lex 2016/2235 (Wayback), ChemSafetyPro |
| EPA: 19 alternatives, none clearly safer | EPA DfE 2014 (single source, primary document) |
| Brother limits 16–43 / 61 lb and 17–58 / 79 lb bond | Brother pages (each its own printer; examples only) |
| Weight answer bands: 75 to 80 gsm (20 to 21 lb bond); 176 to 216 gsm (65 to 80 lb cover); 300 gsm (140 lb) | Wikipedia bond paper, mcgpaper, Hammermill; Cardstock Warehouse, Clear Print; Paul Rubens, Edinburgh, Arches |
| Receipt rolls about 58 or 80 mm wide, up to 83 mm diameter | Epson TM-T88VI, Citizen CT-E351 (Epson TM-U220 also 83 mm) |
| EU thermal paper: BPA 29% in 2019; BPS forecast 61% by 2022 | ECHA release and ECHA report (one survey, two documents) |

## Dropped

- Opacity as a facet. Real for double-sided printing (Wikipedia, inkjet paper, bleed-through) and named in ASTM D 3458 (McCrady), but I could not fetch an office-paper spec sheet that lists it, so no values or listing evidence.
- Recycled content and FSC/SFI. On Hammermill titles ("30% Recycled") but it fails the generic test (it would read the same for toilet paper or bin bags) and AGENTS rule 5 treats certifications as dead.
- Colour and core colour of cardstock. Visual (AGENTS rule 1). Construction paper's fading is noted above only.
- Sheet count and pack size as facets. Generic; used in the price-per-area metric instead.
- Coating chemistry of photo paper (microporous versus swellable). mcgpaper names "microporous coating" once; no second source on what the buyer gains.
- Deckle edges, watermark, felt versus wire side. Real in handprint and Arches, but they are presentation details, not choices that narrow the set.
- Thermal paper image life (years before fading). No fetched source with a number.

## Trimmed detail

- `basis_weight_gsm`: Wikipedia's paper-density page says basis sheets are "usually 17.5 inches by 22.5 inches", which disagrees with every chart (17 × 22 in for bond). I followed the charts; the computed factors reproduce their gsm values.
- `brightness`: Wikipedia, copy paper gives ISO 80 to 96 percent for copy paper while the bleaching article says printer paper can reach 104 ISO. Both may be true for different decades; I avoid giving an ISO range.
- `permanence`: ASTM D 3208/3290/3301/3458 define three permanence levels for office papers (McCrady); only Type I needs the 2 percent reserve. Not a buyer-facing distinction.
- `fibre_content`: linen papers "cockle or warp excessively when wet" (handprint), which is why cotton displaced linen in watercolour paper.
- `thermal_developer`: Suffolk County, New York banned BPA receipts from 3 January 2014 (Wikipedia, "Safer Sales Slip Act", US$500 penalty). Not checked against the county's own text.
- `surface_texture`: Fabriano makes a "soft pressed" finish between hot and cold (handprint).

## Script problems

- `schema.json` restricts `vertical` to formulations, machines, fashion, furnishing, other. The brief requires `vertical: supplies`. With `supplies`, validate.py reported exactly one schema error and nothing else. Resolved in the blind-check fixes by setting `other` (see Corrections); the catalog keeps `supplies`.

## Corrections after the blind check (2026-10-25)

Checker report: `check.md` (16 required fixes). One line per change.

1. Fix 1, weight question: `basis_weight_gsm` question is now "Standard weight, or lighter or heavier than usual?", with a contiguous mapping per family (lighter below the band, heavier above): printer paper 75 to 80 gsm (20 to 21 lb bond), cardstock 176 to 216 gsm (65 to 80 lb cover), watercolour 300 gsm (140 lb). The wrong "160 to 300 gsm (65 to 110 lb cover)" mapping and its 121 to 159 gsm gap are gone; 100 lb text, 67 lb bristol and 50 lb cover now fall in "lighter" on the cardstock branch and "heavier" on the printer branch.
2. Fix 1, art branch: the weight question is no longer asked of all art paper; it moved to the `intended_medium` wet branch, where the 300 gsm mapping is the painter's own term.
3. Fix 1, labels: brand "heavyweight" labels disagree (Hammermill 199 gsm, Cardstock Warehouse "everyday" at 216 gsm), so the cardstock band follows the cover chart; logged under Sources as our call.
4. Fix 2: `brightness` removed from the printer-paper then_ask.
5. Fix 3: dropped "Most of a high brightness number is the brightener" from `optical_brighteners`; it now says ISO brightness above 100 comes from brighteners (Wikipedia, bleaching). Judgement 2 reworded the same way; its note now says brightness is measured at 457 nm rather than "both" scales; the seed "kept" line says "inflated by brighteners"; the brightness trade-off says "a white above 100 on the ISO scale".
6. Fix 4, roll size: `roll_size` re-sourced from Epson TM-T88VI, Citizen CT-E351 and Epson TM-U220 spec pages and two roll stores (POSPaper, Till Rolls Direct). The listing hint was wrong for US stores, which give width by length in feet, not diameter; the facet now says so and forbids converting length to diameter. Thermal → `roll_size` leg is now SUPPORTED.
7. Fix 4, family mapping: `paper_family` value "thermal receipt rolls" renamed "receipt and thermal paper" and defined to include thermal sheets for portable printers and plain or 2- and 3-ply register rolls; split question now "Printer paper, cardstock, art paper, or receipt and thermal paper?". Added a mechanism family for register rolls; `thermal_developer` is left blank for them; thermal sheets use `sheet_size`.
8. Fix 5: `intended_medium` now says lighter sheets are more likely to buckle and are stretched or used as a block; the split rationale says 300 gsm is the usual default, not floor; judgement 4's claim and note were softened the same way (the "taped down" detail about the Edinburgh tutor was not in the source and was removed).
9. Fix 6: `grain_direction` and `caliper_pt` removed from the cardstock then_ask; `printer_compatibility` comes first there and its question is now "Which printer model, or inkjet, laser, or not printing?", which gives `fits_printer` its input and lets hand crafters opt out. The facet text says how a model and "not printing" map.
10. Fix 7: the `intended_medium` branches were rebuilt. The drawing → `surface_texture` leg is dropped; the wet branch (now also taking mixed media) asks `basis_weight_gsm` and `fibre_content`, which no longer sit on the art-paper branch, so it changes the path.
11. Fix 8: scope boundary added to the `paper_family` backfill note (boards to `stationery-boards`, bound sketchbooks to `notebooks` with loose art pads and blocks staying here, sticker, vinyl and label sheets to `labels`, card blanks to `cards`); "vinyl, synthetics" removed from `printer_compatibility`, replaced by the three mcgpaper products actually read.
12. Fix 9: the art-paper → irrelevant `brightness` leg now states the missing step in the Branches trace; the `brightness` backfill note says art papers name a colour and that brighteners go under `optical_brighteners`; Arches reference gained that support line.
13. Fix 10: `coating_finish` question is now "Plain, matte, satin, or glossy?"; backfill note maps plain to uncoated.
14. Fix 11: `basis_weight_gsm` backfill raised to medium (low for bond and art paper, medium for cardstock without a grade); `fibre_content` backfill raised to medium with a hint that only brand pages were seen; `optical_brighteners` inference limited to stated ISO values above 100.
15. Fix 12: ECHA's 2020 release and report added as references; the `thermal_developer` judgement note now gives BPA 29% (2019) and BPS 61% forecast (2022) and says the EU ban names BPA only; the facet text says BPS was under separate EU evaluation in 2020. The two ECHA documents are one survey; no third source was reachable without search.
16. Fix 13: `caliper_pt` backfill note now says caliper varies by 5 to 7 percent with manufacturing (mcgpaper); the mcgpaper reference line was corrected the same way.
17. Fix 14: Hammermill's 110 lb card is described as 199 gsm, matching index weight, with the grade not named by Hammermill, in judgement 1, the weight backfill note and the Hammermill reference. The summary keeps "110 lb is 199 gsm as index", which Clear Print (200) and the computed factor support.
18. Fix 15: `fits_printer` now says "US printer pages state limits in pounds bond" and depends on the model from the printer question.
19. Fix 16: `vertical` set to `other`, the schema's catch-all, as most Supplies registers in this folder did; the catalog entry still says `supplies` and the publish step groups by the catalog. The real fix is a `supplies` value in the skill's schema, which this run must not edit.
20. Not changed, from Part B and D notes outside the required list: acrylic, oil, marker and printmaking papers still have no `intended_medium` value (no source read on how they are sold); wide-format inkjet rolls still have no size facet; the US-only basis of the Brother examples is now stated rather than broadened. Open: `stationery-boards` routes flip-chart and poster paper pads to `paper`, but this register has no family for them; left for the next pass rather than invented.

No finding was rejected.