# Refills, leads and ink cartridges: research notes

Date: 2026-10-25. Scope: consumable refills for writing instruments: ballpoint, gel, rollerball and multi-pen refills; fountain pen cartridges, converters and bottled fountain pen ink; mechanical pencil and leadholder leads; marker and highlighter ink refills. Not printer ink or toner (machines / electronics `printer_accessories`, whose add-on already has `accessory_type: ink_cartridge`), not drawing or India inks and alcohol inks sold as art media (supplies / crafts `paint`, "Paints, Inks & Dyes"), not the pens or pencils themselves (siblings `pens` and `pencils`), and not eraser refills (left to `pencils` and `correction-products`). Overlap: refill multipacks bundled with a pen belong to `pens`; colour marker refill sets marketed for art overlap with crafts `paint` and are left to it where the listing sells them as art ink.

Quote labels: **verbatim** = the sentence in quotation marks was in text I read myself (curl plus HTML stripping, or Wikipedia raw wikitext), or the fetch tool returned it in quotation marks; **fetched excerpt** = the fetch tool summarised or lightly reworded the page; **search excerpt** = from a search-engine summary. This run had no web search (the session's search budget was spent before it started), so every source was fetched by URL and there are no search excerpts.

Vertical: the brief asks for `"vertical": "supplies"`, but the skill's `schema.json` enum is formulations, machines, fashion, furnishing, other. `supplies` fails validation, and `publish.py` would publish the register as `invalid`. The JSON uses `other` so it validates. See "Script problems" at the end.

## Seed

Seed output, verbatim:

```
=== Example entry (from an unrelated category) ===
category: car-tyres
what this shows: a number that is on every listing and still needs a judgement attached, because experts know it only compares within one manufacturer's range.
(treadwear_grade example entry and its judgement: "Treadwear grades can be compared across brands as a rough guide but not as a ranking.")

=== Persona ===
An allergist, who thinks in exposure, dose and what is hidden in the ingredients list
```

(The example JSON block is the standard car-tyres `treadwear_grade` entry from `examples/tyres-treadwear.md`, printed in full by the script; abbreviated here.)

1. **The refill equivalent of treadwear is the pencil lead grade.** It is in the title of every lead listing we read (Goldspot: "Lead Refill - HB - 0.5mm"), buyers compare on it, and it only compares within one maker. Wikipedia (Pencil): "Manufacturers distinguish their pencils by grading them, but there is no common standard." Pencils.com: "there is no specific industry standard for the darkness of the mark to be left within the HB or any other hardness grade scale" and "an HB lead produced in Japan is generally softer and darker than an HB from European producers." **Kept** as `lead_grade` with judgement 1. A second treadwear analogue is the point size: Japanese refills state a ball diameter, Western refills an F/M/B line label, and Wikipedia says the ball "does not correspond to the width of the line". **Kept** as the `tip_size` judgement. Writing length in metres per refill was the obvious analogue but I found no two sources with numbers; **dropped**.
2. **The allergist notices what is hidden in the ink, and what it does to the pen.** Survived: (a) fountain ink chemistry (dye, pigment, iron gall), because the hidden ingredient decides whether the ink clogs or corrodes the pen; kept as `fp_ink_type`. (b) US art-material hazard labelling: 16 CFR 1500.14 says LHAMA does not reach "common wood pencils, and single colored pens, markers, and chalk" unless marketed as art; kept as a judgement. (c) "There is no lead in pencils" (pencils.com) and Schmidt's "All stainless steel tips are lead-free"; kept as a judgement. **Dropped**: skin contact or allergy facets for ink; no source treats refills that way.

## Sources and what each supports

### Standards and regulators

**ISO 12757-2:1998, Ball point pens and refills, Part 2: Documentary use (DOC)**
https://www.iso.org/standard/23718.html (live page returned Cloudflare challenge to curl and 403 to the fetch tool; read via Internet Archive, https://web.archive.org/web/2024/https://www.iso.org/standard/23718.html and the 2005 catalogue snapshot)
- verbatim (2024 snapshot): "ISO 12757-2:1998 Ball point pens and refills Part 2: Documentary use (DOC) Published (Edition 1, 1998) This publication was last reviewed and confirmed in 2020. Therefore this version remains current."
- verbatim (2005 snapshot): "Number of pages: 5 Technical committee / subcommittee: TC 10".
- Supports: a documentary-use grade exists for ballpoint refills. I could not read the standard's content, so the register does not say what DOC tests. Confidence high for existence, none for content.

**Wikipedia, Ballpoint pen (Standards list)** also lists "ISO 14145-2:1998: Roller ball pens and refills – Part 2: Documentary use (DOC)" (verbatim). Second source for ISO DOC grades existing for rollerballs.

**16 CFR 1500.14(b)(8), via Cornell LII** https://www.law.cornell.edu/cfr/text/16/1500.14
- verbatim: LHAMA provides that "the requirements for the labeling of art materials set forth in the version of the standard of the American Society for Testing and Materials ["ASTM"] designated D-4236 ... shall be deemed to be a regulation issued by the Commission".
- verbatim: the Commission does not intend to enforce against "(1) Products whose intended general use is not to create art (e.g., common wood pencils, and single colored pens, markers, and chalk), unless the particular product is specifically packaged, promoted, or marketed in a manner that would lead a reasonable person to conclude that it is intended for use as an art material." Factors: "packages of multiple colored pencils, chalks, or markers unless promoted for non-art materials uses are likely to be art materials", "pencils and pens intended specifically for sketching and drawing are likely to be art materials".
- verbatim: "Statement of Conformance—"Conforms to ASTM Practice D-4236," or "Conforms to ASTM D-4236," or "Conforms to the health requirements of ASTM D-4236.""
- Supports: judgement 4 (now 4 of 7). Confidence medium-high; it is the regulation itself.

**CPSC, Art Materials business guidance** (live page "Access Denied"; read via Internet Archive 2025 snapshot, https://web.archive.org/web/2025/https://www.cpsc.gov/Business--Manufacturing/Business-Education/Business-Guidance/Art-Materials)
- verbatim: "A statement of conformance ("Conforms to ASTM Practice D-4236," "Conforms to ASTM D-4236," or "Conforms to the health requirements of ASTM D-4236") must be placed whenever practicable on the product; if not practicable, it may instead be placed on the package".
- Supports: second source for the conformance wording. It does not repeat the pens exclusion in the text I read, so the exclusion rests on the CFR alone.

### Brand spec sheets

**Schmidt Technology, Refills** https://www.schmidttechnology.de/en/products/writing-instruments-technology-2/refills/
- verbatim: "available in the worldwide accepted large capacity refills G2 format"; "Because the Softline refill is designed in the universal G2 format, it fits into many of the world's millions of existing writing instruments".
- verbatim: easy FLOW "is available in the large capacity refill size G2 and the D style as per the standard DIN ISO 12757."
- verbatim: "Nearly all of the world's major brands in the writing instruments industry rely on our company's high-quality, innovative and reliable refills." (maker's claim)
- verbatim: "S 8126 Capless rollerball refill ... 0.6 mm ceramic ball ↔ 108,6 mm Ø 6.9 mm" and "P 8126 Capless rollerball refill ... 0.6 mm ceramic ball, one year cap-off time ↔ 97.5 mm Ø 6.9 mm"; "8126 Mini ... ↔ 76 mm".
- verbatim: "All stainless steel tips are lead-free."
- verbatim: easy FLOW 9000 "in G2 format ... 0,8 mm TC ball" and "1.0 mm TC ball".
- Supports: G2 and D formats named against ISO 12757; the same tip in three lengths (so length is part of fit); maker-claim for compatibles. Confidence high for formats.

**Pencils.com, Graphite Grading Scale Explained** https://pencils.com/hb-graphite-grading-scale/
- verbatim: "Most pencil manufacturers outside of the U.S. use this scale, using the letter "H" to indicate a hard pencil. Likewise, a pencil maker might use the letter "B" to designate the blackness".
- verbatim: "In reality however, there is no specific industry standard for the darkness of the mark to be left within the HB or any other hardness grade scale. Thus, a #2 or HB pencil from one brand will not necessarily leave the same mark as a #2 or HB pencil from another brand."
- verbatim: "an HB lead produced in Japan is generally softer and darker than an HB from European producers."
- Confidence high (agrees with Wikipedia).

**Pencils.com, The Unleaded Pencil** https://pencils.com/pages/the-unleaded-pencil
- verbatim: "There is no lead in pencils. Rather, the core is made up of a non-toxic mineral called graphite."

### Primers

**Wikipedia, Ballpoint pen** (raw wikitext)
- verbatim: "Ballpoint tips are fitted with balls whose diameter can vary from 0.28 mm to 1.6 mm. The ball diameter does not correspond to the width of the line produced by the pen." "Some standard ball diameters are: 0.3 mm, 0.38 mm, 0.4 mm, 0.5 mm, 0.7 mm (fine), 0.8 mm, 1.0 mm (medium), 1.2 mm and 1.4 mm (broad)."
- verbatim: "Rollerball pens employ the same ballpoint mechanics, but with the use of water-based inks instead of oil-based inks." Hybrid ink "viscosity is lower than that of standard ballpoint ink, but greater than rollerball ink"; examples "Zebra Surari, Uni-ball Jetstream and Pilot Acroball".
- verbatim caption: "Twist action ballpoint pen with large capacity G2 type refill."

**Wikipedia, Gel pen**
- verbatim: "A gel pen uses ink in which pigment is suspended in a water-based gel." "Many gel inks are water resistant, and are not washed away by water once the ink has dried. Fraud resistant gel ink is unaffected by solvents such as acetone, and resists check washing." Ball "usually between 0.3 and 1.2 mm".

**Wikipedia, Fountain pen (Cartridges, Inks)**
- verbatim: international cartridges "in short (38 mm in length, about 0.75 ml of capacity) or long (72 mm, 1.50 ml) sizes, or both. It is to some extent a standard, so the international cartridges of any manufacturer can be used in most fountain pens that accept international cartridges."
- verbatim: "Some very compact fountain pens (for example Waterman Ici et La and Monteverde Diva) accept only short international cartridges." "Some pens (such as the modern Waterman models) have intentional fittings which prevent the usage of short cartridges."
- verbatim: proprietary cartridges from "Parker, Lamy, Sheaffer, Pelikan, Cross, Sailor, Platinum, Platignum, Waterman, and Namiki". (Note: Goldspot and Nibs list Pelikan as international; the Wikipedia list is inconsistent on Pelikan. The register does not name Pelikan.)
- verbatim: makers of proprietary cartridges "tend to discourage the use of cheaper internationally standardised short/long cartridges ... cheaper ink may also skip or produce uneven colour on the page and "feather"".
- verbatim: "Bottled inks usually cost less than an equivalent amount in cartridges and afford a wider variety of colours and properties."
- verbatim: "Contemporary fountain pen inks are almost exclusively dye-based because pigment particles usually clog the narrow passages." "Traditional iron gall inks intended for dip pens are not suitable for fountain pens as they will corrode the pen". Modern iron gall "can still be corrosive if left in the pen for a long period." "Normal India ink cannot be used in fountain pens because it contains shellac as a binder".

**Wikipedia, Iron gall ink**
- verbatim: "Ferro-gallic deposit accumulation in the feed system can clog the small ink passages in fountain pen feeds. Further, very acidic traditional iron gall inks intended for dip pens can corrode metal pen parts". Same publisher as the fountain pen article; the third source on fountain ink safety is Nibs.com.

**Wikipedia, Mechanical pencil**
- verbatim: "Mechanical pencil mechanisms use only a single lead diameter." "The most common lead sizes are 0.5 mm and 0.7 mm, whose line widths provide a favourable balance between precision and strength." Table 0.20 to 5.60 mm; "0.30 ... (also known as 0.35 mm in certain German manufacturers)"; "0.90 ... (sometimes labeled as 1.0 mm by certain German manufacturers)".
- verbatim: "A clutch pencil (or leadholder) tends to use thicker leads (2.0–5.6 mm)".
- verbatim: "The Japanese JIS standard for mechanical pencil leads, states that the actual diameter for "0.5 mm" lead (for example), should range from 0.55 mm to 0.58 mm." (single source; kept out of the JSON)
- verbatim: "pencil leads ... do not contain the toxic chemical element lead, but are typically made with graphite and clay, or plastic polymers."

**Wikipedia, Pencil (Grading and classification)**
- verbatim: "Manufacturers distinguish their pencils by grading them, but there is no common standard. Two pencils of the same grade, but different manufacturers, will not necessarily make a mark of identical tone nor have the same hardness."

**Goldspot Pens, What Sizes do Ballpoint Pens Come In?** https://www.goldspot.com/pages/what-sizes-do-ballpoint-pens-come-in
- verbatim: "Fine ballpoint pens have tips made to write a line that is 0.8 mm thick or less. Medium ballpoint pens have tips made to write a line that is between 0.9 and 1.2 mm thick. Lastly, broad ballpoint pens produce a line that is 1.3 mm or thicker."
- Supports: F/M/B are line-width labels. Disagrees in basis with Wikipedia's ball-size labels (0.7 fine, 1.0 medium); kept as a disagreement, not a conversion.

**Goldspot Pens, Ballpoint vs. Rollerball Pens** https://www.goldspot.com/pages/ballpoint-pens-vs-rollerball-pens
- verbatim: "these pens don't easily dry out due to their oil-based ink"; "the ink in the ballpoint pen doesn't smudge due to it's fast drying time".
- verbatim: "The rollerball also requires almost three times as much ink as the ballpoint pen and needs to be capped to prevent drying out." (single source for "three times"; the register says "far more ink")

**Goldspot Pens, What are Gel Pens** https://www.goldspot.com/pages/what-are-gel-pens-and-how-do-they-work
- verbatim: "Rollerball pens also use water-based ink, but use dyes instead of pigments". Not cited in the JSON; supports the rollerball family line.

### Specialist retailers (enthusiast-facing; fit charts)

**Goldspot Pens, Cartridge Converter Compatibility Guide** https://www.goldspot.com/pages/cartridge-converter-compatibility-guide-for-fountain-pens
- verbatim: "International cartridges are made in short or long sizes. International converters are made in one size. A variety of manufacturers produce the same style of cartridge or converter and they are all compatible with each other."
- verbatim chart rows: "Pilot Proprietary Proprietary**", "Platinum Proprietary Proprietary", "Sailor Proprietary 2", "Parker Proprietary Proprietary", "Lamy Proprietary Proprietary**", "Montblanc Proprietary Proprietary", "Pelikan Standard International", "Waterman Standard International", "Kaweco Standard International", "TWSBI Standard International". "**These pen brands use multiple cartridge/converter styles."
- Note: refillfinder.com now redirects to Goldspot; I read Goldspot's pages in its place.

**Nibs.com, Fountain Pen Ink Cartridges** (Internet Archive 2016 snapshot) https://web.archive.org/web/2016/http://www.nibs.com/fountain-pen-ink-cartridges.htm
- verbatim: "Cartridges fall into two broad categories-- international and proprietary." "Aurora, Cross, Parker, Platinum, Pilot-Namiki, Sailor, and Sheaffer ink cartridges are proprietary, usable only in their respective pen brands. Aurora and Parker cartridges are mutually compatible".
- verbatim: "Pelikan cartridges fit into pens that use international cartridges and are available in both small and large sizes". "Pilot-Namiki cartridges ... have a capacity of 0.8 ml." (single source; not in JSON)
- verbatim: Sailor pigment inks "are water resistant, quick-drying inks. While we always recommend regular cleaning when using pigment inks, we have found these inks to be very safe for fountain pen use."

**Nibs.com, Pen Maintenance** (Internet Archive, 20160808175217)
- verbatim: "try sticking to carbon or pigment-based inks that are specificially formulated for fountain pens, such as those made by Platinum and Sailor. And whatever ink you use, regular cleaning will help insure your pen's feed system will have a long and happy life."

### News

**WBAY, Consumer First Alert: Use gel pens to write checks (30 April 2023)** https://www.wbay.com/2023/04/30/consumer-first-alert-use-gel-pens-write-checks/
- verbatim (fetch tool, in quotes): "Criminals steal checks from a mailbox and then wash them in chemicals to remove the ink." "Gel soaks into the paper and it's much harder to remove than ballpoint pen ink."

### Retail listings (what fields are present)

**Goldspot, Ballpoint Pen Refills collection** https://www.goldspot.com/collections/ballpoint-pen-refills
- verbatim: "You will see the major formats you are most likely to encounter: Parker-style long (also known as ISO G2; not the same as Pilot G2 gel), Cross-style, LAMY M16, Retro 51's Schmidt EasyFlow 9000 (often listed as REF71), Fisher pressurized (SPR series, sometimes used with a Parker-style adapter), and compact D1 mini refills for slim or multi-pens. Always match the format to your pen model for a proper fit."
- verbatim: "Start by identifying the refill format for your pen." "Don't forget to match the size (F/M/B, EF/DB) and color you prefer."
- verbatim titles: "Schmidt P900 Parker Style Ballpoint Pen Refill in Green by Monteverde - Medium Point"; "Parker D-1 Mini Ballpoint Pen Refill in Blue - Medium Point - Pack of 5"; "Pilot Retract Ballpoint Pen Refill in Red - Fine Point". 27 "Point" labels on the page.

**Goldspot, Mechanical Pencil Lead collection** https://www.goldspot.com/collections/mechanical-pencil-lead
- verbatim titles: "Caran d'Ache Lead Refill - HB - 0.5mm", "Faber-Castell Lead Refill - B - 1.4mm", "Kaweco All-Purpose Colour Lead Refill in Blue - 5.6mm", "Retro 51 Tornado Lead Refill - HB - 1.15mm".
- Diameter counts in titles: 0.5 mm 5, 0.7 mm 6, 0.9 mm 2, 1.15 mm 1, 1.4 mm 2, 2 mm 6, 3 / 3.15 mm 2, 5.6 mm 6.
- Mass-market retailers (Amazon, Staples, Walmart) were not tried in the time available; the earlier runs found them blocked. `source: listing` here rests on specialist-retailer titles plus the add-on's own fields (`lead_diameter_mm`, `lead_grade`, `tip_size_raw`), which the Zamana extractor already expects on listings.

### Could not reach
- JetPens guides and product pages: Cloudflare challenge (403) to curl.
- iso.org live pages: Cloudflare challenge; used Internet Archive.
- Richard Binder's ink page (richardspens.com): JavaScript shell; the archived copy returned 6 words.
- ACMI (acmiart.org) certification page: 404.
- Reddit r/pens and r/fountainpens wikis: not tried; earlier runs found reddit blocked.

## Data points used for derived metrics

`cost_per_ml` has no constants. Capacity data found, for reference only (single-source each, not in the JSON):

| Item | Capacity | Source |
|---|---|---|
| Standard international short cartridge | about 0.75 ml | Wikipedia (Fountain pen) |
| Standard international long cartridge | 1.50 ml | Wikipedia (Fountain pen) |
| Pilot-Namiki cartridge | 0.8 ml | Nibs.com 2016 |

Bottled ink is sold by volume on the label, so a bottle's cost per ml is computable from the listing; a cartridge pack's needs the maker's capacity figure.

## Against the existing add-on schema

Add-on read: `supplies/stationery/add-ons/ink_cartridge.jsonc` (compatibility_raw, tip_size_raw, lead_diameter_mm, lead_grade, oem_or_compatible), composed with `stationery-standard.jsonc` (empty) and `supplies-standard.jsonc` (high_signal_markdown, sizing: pack_count, capacity, weight, dimensions). Field kinds from `zamana-expertise/AGENTS.md`: vertical anchor, category quality currency, hard filter, sizing, or high-signal markdown.

| Facet in this register | In add-on today | Proposed kind | Note |
|---|---|---|---|
| refill_system | no | vertical anchor (enum) | Proposal: `refill_system` enum [ballpoint, gel, rollerball, fountain_pen_ink, pencil_lead, marker_ink, unspecified]. Every other field depends on it; titles state it. |
| pen_model | yes, `compatibility_raw` | hard filter | Keep verbatim. It is what the buyer types. |
| refill_format | no | hard filter (enum) | Proposal: `refill_format` enum [parker_style_g2, d1_mini, cross_style, lamy_m16, fisher_pressurised, brand_specific, not_applicable, unspecified]. Normalised from compatibility_raw plus refill code; this is what lets a Schmidt P900 match a Parker query. |
| cartridge_fit | no | hard filter (enum) | Proposal: `cartridge_fit` enum [international_short, international_long, proprietary, not_applicable, unspecified]. |
| fill_form | no | hard filter (enum) | Proposal: [cartridge, converter, bottled_ink, not_applicable]. Bottle volume already fits `sizing.capacity` (ml). |
| fp_ink_type | no | high_signal_markdown, or a small enum if fountain ink is a large share | Named in the product name when not dye; default dye. |
| tip_size | yes, `tip_size_raw` (string) | hard filter | Proposal: keep raw, add `tip_label` enum [extra_fine, fine, medium, broad, unspecified] and `ball_mm` number, because the two bases differ (see judgement 2). |
| document_proof | no | high_signal_markdown | A keyword pass ("pigment", "archival", "ISO 12757-2", "fraud") is enough; not worth a column. |
| lead_diameter_mm | yes | hard filter | Keep. |
| lead_grade | yes, enum [2h, h, hb, b, 2b, assorted, not_applicable, unspecified] | hard filter | Proposal: add `f`, `3b_or_softer`, `colour`; the current enum cannot hold a 4B drafting lead or a colour lead. |
| maker_or_compatible | yes, `oem_or_compatible` [oem, third_party_compatible, universal, unspecified] | high_signal_markdown | The comment calls it "the third-party trap". For pen refills that framing is wrong (judgement 4): compatible refills are a normal upgrade. Proposal: demote to markdown, or keep with the comment changed. `universal` overlaps `refill_format: parker_style_g2`. |

Add-on fields this register considers noise: none of the five are pure noise. `oem_or_compatible` carries the wrong frame (above). From `supplies-standard`, `sizing.dimensions` and `sizing.weight` are noise for refills: refill length matters for fit, but buyers match it through the format and the pen model, not by reading millimetres; `sizing.pack_count` is useful (cost per refill, cost per lead).

## Branches

Each branch leg traces to a sentence in the register or these notes. Rewritten 2026-10-25 after the blind check: the ball-refill branch is split so rollerball keeps cartridge fit live, a `marker ink` branch is added, and then_ask lists only facets with a buyer question (refill_format, cartridge_fit and fp_ink_type are resolved from pen_model or the product name, so they are shown, not asked, and are neither in then_ask nor irrelevant on the branches where they apply).

**Split 1, refill_system ("Ballpoint, gel, fountain pen, or pencil lead?")**. Answer mapping: the four offered answers are values of the facet; "rollerball" and "marker" answers map to their own values (split rationale). Mixed names are classified by the ink named, so "gel rollerball" and "Gel Ballpoint Refill" are `gel` (refill_system backfill_note).

- when `pencil lead`: then_ask lead_diameter_mm, lead_grade; makes_irrelevant refill_format, tip_size, cartridge_fit, fill_form, fp_ink_type, document_proof, water_resistant.
  - lead_diameter_mm: "A mechanical pencil takes one diameter only, so this is a hard filter" (lead_diameter_mm, why experts care; Wikipedia "Mechanical pencil mechanisms use only a single lead diameter").
  - lead_grade: "leads have diameter and grade" (split 1 rationale).
  - refill_format, tip_size: defined for "a ballpoint, gel or rollerball refill" (refill_format definition) and as "how fine a line the refill writes, labelled ... as a ball diameter" (tip_size definition); a lead has neither.
  - cartridge_fit, fill_form, fp_ink_type: each is defined for "a fountain pen cartridge" or "fountain pen ink" (their definitions).
  - document_proof, water_resistant: defined on "the dried ink" (definitions); leads carry no ink. Chain: no ink, so the facets have no value.
  - ink_colour stays live: colour leads are titled by colour ("Kaweco All-Purpose Colour Lead Refill in Blue - 5.6mm", Goldspot).
- when `fountain pen ink`: then_ask fill_form, ink_colour, water_resistant; makes_irrelevant refill_format, tip_size, lead_diameter_mm, lead_grade.
  - fill_form: "Cartridges are the cleanest swap. Bottled ink ... needs a converter or a piston pen" (fill_form, why experts care).
  - ink_colour: "For bottled fountain ink colour is the main choice" (ink_colour, why experts care; Goldspot sells inks "by Color").
  - water_resistant: "Standard dye fountain inks do not; pigment and iron gall fountain inks do" (water_resistant, why experts care; Goldspot water-resistant inks: "Unlike standard dye based inks, these formulations are designed to stay put even when exposed to moisture"). This replaces the old fp_ink_type leg, whose reason (India ink and dip-pen iron gall) was about inks outside the facet's values; fp_ink_type is now the annotation read from the product name that answers water_resistant on the product side.
  - cartridge_fit is not asked: it is resolved from the pen_model answer and applies only to cartridges and converters, not bottled ink (cartridge_fit definition and backfill_note).
  - refill_format and tip_size irrelevant: both defined for ball refills. Fountain line width is set by the pen's nib, a facet for the `pens` sibling.
  - lead facets irrelevant: defined for pencil leads.
- when `ballpoint` or `gel`: then_ask tip_size, ink_colour; makes_irrelevant lead_diameter_mm, lead_grade, cartridge_fit, fill_form, fp_ink_type.
  - tip_size: "It is the main choice left once the format fits" (tip_size, why experts care).
  - ink_colour: Goldspot, "Don't forget to match the size (F/M/B, EF/DB) and color you prefer."
  - refill_format is not asked: resolved from pen_model (refill_format backfill_note).
  - the rest irrelevant by their definitions (pencil leads; fountain pen cartridges and ink).
- when `rollerball`: then_ask tip_size, ink_colour; makes_irrelevant lead_diameter_mm, lead_grade.
  - Same then_ask legs as ballpoint and gel.
  - cartridge_fit, fill_form and fp_ink_type stay live: Schmidt's "cartridge-rollerball-system PRS follows the functional principle of a fountain pen with common ink cartridges" (schmidt_prs; refill_format value "cartridge rollerball"). Single source; it removes a claim rather than adding one.
- when `marker ink`: then_ask ink_colour; makes_irrelevant lead_diameter_mm, lead_grade, refill_format, cartridge_fit, fill_form, fp_ink_type.
  - ink_colour: the register's only facet that clearly applies to marker refills.
  - refill_format is defined for ballpoint, gel and rollerball refills; the fountain and lead facets by their definitions. tip_size and the permanence facets are left live because nothing in the sources rules them out for markers.

Splits 2 to 4 have no branches. `pen_model` is a text facet; its answer narrows by lookup, not by changing which questions follow. `tip_size` and `ink_colour` answers filter on themselves.

## Trimmed detail

- **lead_diameter_mm.why_experts_care**: "Nominal sizes run slightly large (JIS: a '0.5 mm' lead measures 0.55 to 0.58 mm), and some German makers label 0.3 as 0.35 and 0.9 as 1.0." Wikipedia only; cut because single-source.
- **tip_size.backfill_note**: a ball-size-to-label mapping (1.2 mm up broad, 1.0 medium, 0.7 fine, under 0.7 extra fine) was cut. The first three are Wikipedia's labels only, and the extra-fine cut-off was ours. The backfill now keeps the listing's own word and shows the mm where no word is given.
- **judgements**: a low-confidence judgement "calling any ball under 0.7 mm extra fine is our cut-off" was removed with the mapping.
- **references**: numeric support lines that the body does not use (Wikipedia ball range 0.28 to 1.6 mm, gel ball 0.3 to 1.2 mm, Goldspot line widths 0.8 / 0.9 to 1.2 / 1.3 mm, Goldspot "almost three times as much ink", Schmidt 108.6 / 97.5 / 76 mm lengths) were reworded without the numbers; the figures are quoted above.
- **mechanism.plain**: "keeps for years" replaced with "dries on paper almost at once but does not dry out easily in the refill" (Goldspot: "don't easily dry out", "fast drying time"); the original had no source.
- **splits[3].rationale**: "Most buyers answer no" removed (unsourced).
- **splits[0].rationale**: wording only.

## Corrections

1. 2026-10-25, before first validate: vertical changed from `supplies` to `other` (schema enum; see above and "Script problems").
2. 2026-10-25, STYLE pass: "every listing" overclaims removed from lead_grade and the tip_size rationale (only specialist-retailer titles were read).

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

Report: `check.md` (13 required fixes). One line per change; "Fix n" is the checker's numbering.

1. Fix 1: added `ink_colour` (listing, cost low, split and filter; values black, blue, blue-black, red, green, other colour) with Goldspot refills, water-resistant inks and leads as evidence, and a "Colour swatch grid" visual grammar.
2. Fix 1: made `ink_colour` split 4, replacing `document_proof` as a split (max four splits; document_proof narrowed least and stays a filter with its own question).
3. Fix 1, partly rejected: pack_count is not added as a facet. It fails the generic test (it would read the same for any consumable) and already sits in the add-on as `sizing.pack_count`; it is added to cost_per_ml depends_on instead.
4. Fix 2: split the ball-refill branch; `rollerball` now has its own branch that leaves cartridge_fit, fill_form and fp_ink_type live (Schmidt PRS, single source); added "cartridge rollerball" to refill_format values and a judgement on it.
5. Fix 3: removed "cheques" from the Ballpoint paste typical_for.
6. Fix 4: tip_size why_experts_care restated (F/M/B on the ball at some makers, Wikipedia 0.7 mm fine, Schmidt 0.8 and 1.0 mm both "(M)"; on the line at Goldspot); dropped "Japanese refills state the ball diameter" (unsourced).
7. Fix 4: tip_size backfill_note now matches mm-only listings by ranking within the format; only "1.0 mm ball = medium" has two sources (Wikipedia, Schmidt), so other mm points rank but never exclude. No conversion range invented. Judgement 2 note and evidence updated (Schmidt added).
8. Fix 5: document_proof redefined as fraud resistance or an ISO DOC grade; added ISO 27668-2:2009 (gel DOC) and an ISO ICS 01.100.40 listing reference covering 12757-2, 14145-2 and 27668-2; DOC described as "minimum quality requirements" (ISO abstract), not proof against washing.
9. Fix 5: the double question is split: new `water_resistant` facet ("Must it survive water once dry?"); document_proof asks "For cheques or documents that must resist tampering?". A yes on document_proof drops ballpoint without a DOC grade (WBAY) and dye inks.
10. Fix 5: "dye fountain ink washes off" now sourced and softened to "does not resist water": Goldspot water-resistant inks ("Unlike standard dye based inks, these formulations are designed to stay put even when exposed to moisture") and Wikipedia Fountain pen ("non-corrosive, though this generally excludes permanence"). Mechanism, fp_ink_type and tradeoff 2 reworded.
11. Fix 6: LHAMA judgement restated as CPSC enforcement policy under 16 CFR 1500.14(b)(8)(iv)(A)(1); notes it names pens and pencils, not refills, and that multi-colour packs are likely art materials; marked single-source.
12. Fix 7: then_ask now holds only askable facets; refill_format and cartridge_fit marked `source: derived` with "Not asked: resolved from the pen_model answer"; fp_ink_type marked "Not asked: shown as an annotation"; cartridge_fit defined as not applying to bottled ink. The fountain fp_ink_type leg is replaced by water_resistant.
13. Fix 8: added a `marker ink` branch (then_ask ink_colour; lead, fountain and refill_format facets irrelevant).
14. Fix 9: maker_or_compatible to `derived`, cost low, hint warns that Goldspot puts the pen brand first for compatibles; refill_system, tip_size and lead_grade cost none to low; refill_system gets a mixed-name rule (classify by ink named) and a printer ink/toner exclusion in the hint; fill_form backfill_note says its listing status is untested.
15. Fix 9 (Part D): refill_format note says "small and stable code set" is our unverified assumption and formats cross over (Fisher with Parker adapter); cartridge_fit cost low to medium, with Platinum-with-adaptor and Lamy-fits-Parker (Wikipedia) added to why_experts_care, replacing "fit only their own pens".
16. Fix 10: lead_grade values now "3H or harder", 2H, H, F, HB, B, 2B, "3B or softer", "colour (no grade)"; the grade scale spans only the values list, and the 9H to 9B chart is labelled as wood-pencil range. The Wikipedia 4H to 4B mechanical-lead range is single-source, so it is not used as the axis.
17. Fix 11: judgement 1 marked single-source (pencils.com; Wikipedia cites it), confidence high to medium; lead_grade why attributes the Japanese HB line to pencils.com.
18. Fix 11: removed Schmidt's lead-free tips from judgement 5 and from schmidt_refills supports.
19. Fix 11: added the Goldspot gel page as reference `goldspot_gel` (rollerball "use dyes instead of pigments"), cited on the mechanism and refill_system.
20. Fix 12: pen_model label "Pen brand, line or format it fits", definition and why reworded to the level listings state; question now "Which pen is it for, or which refill does it replace?" with the old refill's name as fallback (Goldspot: "check the format in the listing details").
21. Fix 13: cost_per_ml depends_on adds capacity and pack_count (add-on sizing fields); why says undefined for converters and for cartridge packs without a published capacity.
22. Part A row 1 (not a numbered fix): dropped "0.5 and 0.7 mm are the common sizes" (Wikipedia only; Goldspot titles show 2 and 5.6 mm as often); now attributed as Wikipedia's precision-strength balance point in lead_diameter_mm, its range note and tradeoff 4.
23. Part A row 7: removed schmidt_refills from tradeoff 1 evidence (says nothing on ink use); "far more ink" stays as Goldspot's single-source wording, no number.
24. Summary reworded to add colour and drop the "name X, then Y" sequence, which ordered questions outside branches; split 4 rationale written without sequence words.
25. Vocabulary: "Documentary (DOC) ink" reworded to minimum quality; added "Cartridge rollerball" and "Blue-black".
26. Rejected nothing else. Not acted on: the art colour-lead overlap with `pencils`/`paint` (Part B scope note), left as in the scope paragraph above, since it is not among the required fixes.

### Sources added after the blind check

- **Schmidt Technology, Fountain Pen Technology / Cartridge-Rollerball-System** https://www.schmidttechnology.de/en/products/writing-instruments-technology-2/fountain-pen-technology-cartridge-rollerball-system/ (curl, stripped). verbatim: "The SCHMIDT® cartridge-rollerball-system PRS follows the functional principle of a fountain pen with common ink cartridges. The writing tip is used again and again and will not be discarded." Single source; no second source found (web search budget spent; Wikipedia Rollerball pen and Goldspot rollerball refills say nothing on it).
- **Schmidt Technology, Refills** (re-read): verbatim "FL 6040 F ... 0.8 mm (M)" and "FL 6040 M ... 1.0 mm (M)".
- **ISO 27668-2:2009** (Internet Archive 2024, https://web.archive.org/web/2024/https://www.iso.org/standard/44271.html). verbatim: "ISO 27668-2:2009 establishes minimum quality requirements for gel ink ball pens (refillable or non-refillable) and refills for documentary use." "This standard was last reviewed and confirmed in 2021."
- **ISO ICS 01.100.40 listing** (Internet Archive 2024, https://web.archive.org/web/2024/https://www.iso.org/ics/01.100.40/x/). verbatim rows: "ISO 12757-2:1998 Ball point pens and refills — Part 2: Documentary use (DOC)", "ISO 14145-2:1998 Roller ball pens and refills — Part 2: Documentary use (DOC)", "ISO 27668-2:2009 Gel ink ball pens and refills — Part 2: Documentary use (DOC)". With Wikipedia's standards list, two sources for 14145-2.
- **Goldspot, What are Gel Pens** (curl). verbatim: "Rollerball pens also use water-based ink, but use dyes instead of pigments to color the ink."
- **Goldspot, Water-Resistant Inks collection** https://www.goldspot.com/collections/water-resistant-inks (curl). verbatim: "Unlike standard dye based inks, these formulations are designed to stay put even when exposed to moisture or accidental spills." "Some dye wash is possible under heavy soaking depending on the paper." "Permanent Built for documentation, contracts, and professional records ... Pigmented options like Platinum Carbon or Sailor Seiboku". "Avoid letting pigment or iron gall inks dry out inside the nib". Titles carry named shades ("Noodler's Fox Red Fountain Pen Ink - 1oz", "Sailor Bottled Ink in Souboku (Deep Blue Pigmented) - 50 mL"); site menu has "Inks by Color".
- **Goldspot, Ballpoint Pen Refills** (re-read). verbatim: "Choose the Ink Color Whether you're looking for something classic like black or blue, or want to add a pop of personality with red, green, or turquoise"; "Don't forget to match the size (F/M/B, EF/DB) and color you prefer."; "If you are unsure which refill fits, check the format in the listing details or ask our team."
- **Wikipedia, Fountain pen** (re-read raw). verbatim: "Platinum (with adaptor)" among international-cartridge brands; "(Lamy cartridges, though not officially, are known to interchange with Parker cartridges also)"; "Inks ideally should be fairly free-flowing, free of sediment, and non-corrosive, though this generally excludes permanence".

## Script problems

- `validate.py` / `schema.json`: the `vertical` enum lacks `supplies`, while `catalog.json` and the workflow brief use `supplies` for this whole run. Every Supplies register written as briefed will fail validation and publish as `invalid`. This register uses `other`. Fix belongs in the skill's schema (add `supplies` to the enum), which this run must not edit.
- render.py and viewer.py ran clean.