Sources and Version Snapshot

Research refreshed 2026-07-23 with parallel-cli search and parallel-cli extract. API and publisher requirements below use current official project, standards-body, publisher, or journal sources only. “Accessed” is 2026-07-23 unless another date is stated.

Tested direct package snapshot

• Matplotlib 3.11.1, released 2026-07-18; Python >=3.11 [MPL-PYPI].
• Seaborn 0.13.2, released 2024-01-25; Python >=3.8 [SEABORN-PYPI].
• Plotly 6.9.0, released 2026-07-09; Python >=3.8 [PLOTLY-PYPI].
• Kaleido 1.3.0, released 2026-05-04 [KALEIDO-PYPI].
• Pillow 12.3.0, released 2026-07-01; Python >=3.10 [PIL-PYPI].
• pypdf 6.14.2, released 2026-06-23; Python >=3.9 [PYPDF-PYPI].

These are pinned direct-dependency snapshots used for smoke tests, not a transitive lock.

Matplotlib

• [MPL-PYPI] matplotlib on PyPI — current package version and release history; page dated 2026-07-18.
• [MPL-RELEASE] Matplotlib release notes — 3.11 release/API changes.
• [MPL-SAVE] matplotlib.figure.Figure.savefig — 3.11.1 signature; format inference, DPI, metadata, bounding boxes, transparency, backends, Pillow kwargs; built 2026-07-18.
• [MPL-BACKENDS] Backends — interactive versus static renderers; PDF/PS/SVG/PGF/Cairo formats.
• [MPL-STYLE] Customizing Matplotlib with style sheets and rcParams — rc_context, style composition, save settings, PDF/PS/SVG font types; built 2026-07-18.
• [MPL-LAYOUT] Constrained layout guide — layout="constrained", colorbars, subfigures, GridSpec, interaction with tight_layout.
• [MPL-GRIDSPEC] matplotlib.gridspec — current grid layout API.
• [MPL-NORM] Colormap normalization — Normalize, LogNorm, CenteredNorm, SymLogNorm, PowerNorm, BoundaryNorm, TwoSlopeNorm; built 2026-07-18.
• [MPL-CMAP] Choosing colormaps — data classes and perceived lightness.

Seaborn

• [SEABORN-PYPI] seaborn on PyPI — 0.13.2 package metadata and release history.
• [SEABORN-ERROR] Statistical estimation and error bars — current errorbar methods, callable intervals, bootstrapping, seed, and n_boot.
• [SEABORN-FAQ] Frequently asked questions — axes-level versus figure-level functions, Matplotlib object-oriented integration, DPI/SVG notes.
• [SEABORN-PALETTE] Choosing color palettes — qualitative, sequential, and diverging palette APIs.
• [SEABORN-THEME] seaborn.set_theme — style, context, palette, font, scale, and rc parameters.

Plotly and Kaleido

• [PLOTLY-PYPI] plotly on PyPI — 6.9.0 package metadata; released 2026-07-09.
• [PLOTLY-STATIC] Static image export in Python — Kaleido/Chrome setup, formats, write_image, write_images, dimensions/scale, WebGL rasterization, offline assets, defaults, EPS/Orca/engine deprecations; page dated 2026.
• [PLOTLY-HTML] Interactive HTML export — write_html, to_html, include_plotlyjs, full_html; page dated 2026.
• [PLOTLY-CHANGES] Static image generation changes in Plotly.py 6.1 — Kaleido v1 migration and deprecations.
• [KALEIDO] Plotly Kaleido repository — Chrome requirement, v1 migration, direct APIs, and offline/page behavior.
• [KALEIDO-PYPI] kaleido on PyPI — 1.3.0 package metadata; released 2026-05-04.

Accessibility and color

• [WCAG22] Web Content Accessibility Guidelines (WCAG) 2.2 — W3C Recommendation; normative SC 1.1.1, 1.4.1, 1.4.3, 1.4.5, and 1.4.11.
• [WCAG-NONTEXT] Understanding SC 1.4.11: Non-text Contrast — informative chart/graph examples and testing principles; not itself normative.
• [WCAG-COLOR] Understanding SC 1.4.1: Use of Color — informative non-color cue guidance.
• [COLORBREWER] ColorBrewer 2.0 — Cynthia Brewer, Mark Harrower, and Penn State; scheme type, data-class count, colorblind/print/photocopy filters, and exports.
• [TOL-HOME] Paul Tol’s Notes — canonical site; page states the move from SRON on 2026-07-07.
• [TOL] Paul Tol, “Colour Schemes” — SRON/EPS/TN/09-002, issue 3.2, 2021-08-18; exact sRGB palettes, intended uses, color-vision checks, and grayscale analysis.
• [WONG] Bang Wong, “Color blindness” — Nature Methods 8, 441 (2011); source commonly used for the eight-color palette.

Publishers and journals

All rules were accessed 2026-07-23. Pages without a displayed update date are labeled by access date rather than assigning an invented publication date.

• [NATURE-FINAL] Nature final submission — flagship final files, dimensions, fonts, formats, raster resolution, RGB/CMYK, Extended Data distinctions.
• [NATURE-FIG] Nature research figure specifications — graphs, accessibility, RGB, 300/450 dpi discussion, editable Type 42 text, export.
• [SCIENCE-INITIAL] Science initial manuscript instructions — initial figure embedding, 300 dpi, widths, fonts, color/contrast, source data.
• [SCIENCE-REVISED] Science revised manuscript instructions — separate files, formats, minimum resolution, dimensions, no upsampling.
• [CELL-FIG] Cell Press figure guidelines — initial versus final stages, formats, widths, file size, DPI, RGB, fonts, image integrity, AI-assisted image policy.
• [PLOS-FIG] PLOS Computational Biology figures — provisional-accept waiver, TIFF/EPS, dimensions, 300-600 dpi, RGB/grayscale, file size, image integrity, 2026-04-01 blot/gel requirement.
• [ELSEVIER-FORMAT] Elsevier artwork formats checklist — general formats, RGB preference, separate files, journal override.
• [ELSEVIER-SIZE] Elsevier artwork sizing — general widths, 300/500/1,000 dpi, typography, and explicit journal variability.
• [IEEE-SIZE] IEEE Resolution and Size — modified 2025-02-25; PS/EPS/PDF, >300/>600 dpi, 88.9/182 mm.
• [BMC-BIOINFO] BMC Bioinformatics: preparing your manuscript — journal-specific formats, 85/170 mm, approximately 300 dpi, 10 MB, embedded fonts.
• [ACS-GRAPHICS] ACS Preparing Manuscript Graphics — general dimensions and typography; no page update date displayed.

Optional inspection backends

• [PIL-PYPI] Pillow on PyPI — 12.3.0 package metadata; released 2026-07-01.
• [PYPDF-PYPI] pypdf on PyPI — 6.14.2 package metadata; released 2026-06-23.

No Parallel JSON research artifacts are stored in this skill.