# Latent Image — design system

The visual system for Pantagruel's Pen (pantagruelspen.com) and adjacent work.
This file is the short form, written for agents and for anyone who needs the
rules without reading the full document.

Canonical artefacts:
- /                  the full specification, rendered (Rev. C)
- /tokens.json       machine-readable palette, type and scale
- /rev-c.html        the specification, direct link
- /rev-b.html        previous revision (five pigments, nine candidate faces)
- /rev-a.html        first exploration (superseded)

## The one-paragraph version

The identity is a printed plate: a grid, plate numbering, figure references, a
three-role type split, two rule weights, and corner registration marks. That
core is medium-blind — it renders as ink on bone in a paper, as light on ink in
a browser, as vinyl on cotton on a shirt. Screen treatment (afterglow, grain,
live drawing) sits on top as a finish, applied only where there is a backlight.
Strip the finish and the layout is unchanged.

## Registers

PLATE   ink on bone. The printed register and the default. One pigment, no
        second tone, no glow. On paper a second hue almost always means the
        hierarchy failed to work with position and weight.
LATENT  light on ink. The read-out register. A second tone is permitted here
        because a screen can decay: a mark strikes bright and settles toward
        the ink it would have been on paper.

Rule that generalises: a system's LATENT `settle` value IS that system's PLATE
`mark` value. Any pigment added later inherits this for free.

## Pigment

Colour is selected by one rule: a hue must name a substance with a chemistry
and a date. Two systems are in use.

CYANOTYPE (primary, 1842) — ferric ammonium citrate + potassium ferricyanide.
  plate:  ground #e9e4d7  ink #0f3050  mark #0f4c81  settle #0f4c81
  latent: ground #06131f  ink #dce9f5  mark #8fb6ff  settle #0f4c81
  The latent `mark` is the P7 phosphor emission — legitimate on a screen,
  which emits rather than prints.

VERDIGRIS (sibling, antiquity) — copper acetate. A mineral green, blue-leaning
and desaturated: the colour of a roof, not a highlighter.
  plate:  ground #e7e7dd  ink #141613  mark #2f6b5e  settle #2f6b5e
  latent: ground #071110  ink #dceae3  mark #7fe0c2  settle #2f6b5e

One pigment per artifact. Full values in /tokens.json.

## Type — three roles, one face each

DISPLAY  Syne, weight 700, tracking -0.035em. Mastheads, titles, section
         heads. Never running text, never under 12px.
         Do not use 800: Syne's upper weight is a much wider cut, not simply
         a bolder one.
PROSE    Literata, 17px / 1.62 / 66ch, italic available. Essays, abstracts,
         deks, quotes, mathematical variables.
DATA     Departure Mono, 400, at 8/10/12px, tracking 0.07em, uppercase,
         tabular numerals. Labels, dates, counts, plate and figure numbers,
         code, provenance.

The split is the point: monospace appears only where a machine produced the
value, so its presence is information. If a human wrote it, it is not set in
Departure Mono.

All three are OFL and self-hosted. No third-party font requests.

## Six principles

1. Nothing warns. No sirens, chevrons, reticles, classification stamps, or a
   red that means stop. Almost every visual language for "the future" was
   drawn to depict misalignment; this one is not.
2. Seams, not seamlessness. Show the joins — what was revised, what is
   uncertain, what a machine contributed and where.
3. Two readers, one document. Legible to a person at 66 characters and
   parseable by a machine, neither degraded for the other.
4. Continuity with deep time. Post-human is not post-history.
5. Things that age. Persistence and decay are real mechanics.
6. Pigment, not RGB. Every colour names a substance.

## Null results

Position: a null is a result with a mark of its own, never an absence.

Three devices, used together:
- Hollow marks (○) drawn rather than omitted; filled (●) for an effect;
  an em dash (—) for not tested.
- An equivalence band, always drawn, so a null has somewhere to sit.
- A standing null register with the same type weight as the results.

Never grey a null. Grey reads as less important, which is the exact
misreading the whole exercise exists to prevent.

## Chrome vocabulary

Eight named parts, each holding one kind of information and appearing in one
place: register line, eyebrow strip, provenance line, registration marks,
margin note, plate number, standing intentions, null mark.

## Imagery

Two doors. Photographs and thumbnails pass through error diffusion to exactly
two tones, so images are on-palette by construction rather than by filtering.
Heroes and dividers are generative line — flow fields and wireframe solids
drawn live, at no payload cost.

## If you are generating something in this system

- Pick one pigment and stay in it.
- Use the register that matches the medium: Plate for print, Latent for a
  dark screen.
- Set display type at 700, prose at 66 characters, labels in the data face.
- Two rule weights, no vertical rules in tables.
- Do not introduce a warning colour. There is nothing to warn about.
- If you need a colour that is not here, name the substance first.