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DFT Category-10 Development History

Status: draft Scope: preservation note for the DFT default categorical palette selection process Source: DFT Color Palettes, Default Categorical Palette, palette engineering artifacts in color-palettes-assets/

This note exists to preserve the thinking, decision points, and artifact trail behind the current DFT category-10 palette. It is not the canonical product spec; that role belongs to Default Categorical Palette.

For the broader M2 palette program that built on top of this work — the sequential/diverging/semantic palette system, the Leonardo + Colorgorical scoring infrastructure, and the tonal monochromatic family — see the internal record at ai_notes/considerations/DFT_PALETTE_QUALITY_PROGRAM_2026.md.

Stable Outcome

The current stable DFT category-10 sequence is:

  1. blue #2d74b3
  2. cyan #4cb6d3
  3. green #4e9c78
  4. brown #8a6744
  5. gold #bf9638
  6. purple #9c6fa7
  7. orange #cd6d40
  8. moss #6d8a47
  9. gray #87909d
  10. charcoal #56616f

Earlier Stable Direction

Before the current stable palette, DFT had an earlier working category-10 that was itself a meaningful step forward and should be preserved as part of the same story:

  1. blue #2d74b3
  2. gold #c08a2c
  3. green #53a06f
  4. lilac #ac73b2
  5. brown #8a6744
  6. orange #cd6d40
  7. sand #b59b73
  8. olive #7a8240
  9. gray #87909d
  10. charcoal #47515d

That earlier palette belongs in the history, not in the trash. It established:

  • the blue-led posture
  • the calm, editorial tone
  • the choice to avoid ordinary early categorical red
  • the idea that later slots could quiet down into earths and neutrals

The later round did not reject that framing. It refined it.

Canonical Current Homes

These are the places that should describe the live palette:

Development Trail

The core design trail now lives in the guide set rather than in an external spreadsheet or ad hoc Downloads folder:

Relevant task roots for the same story:

  • tasks/workstreams/graph-library/tasks/define-initial-chart-color-palette-system.md
  • tasks/workstreams/graph-library/tasks/refine-hero-vs-warms-categorical-palette.md
  • tasks/workstreams/graph-library/tasks/m1-consistent-category-color-mapping-across-charts.md

Major Phases

Phase 1: establish the first real DFT category-10

This phase produced the earlier blue / gold / green / lilac ... palette and set the basic DFT stance:

  • blue-led, not rainbow-led
  • calmer than generic BI defaults
  • later earths and neutrals are acceptable
  • accessibility matters, but so does whole-chart feel

Phase 2: corpus and structural analysis

This phase deepened the process:

  • preserve the external palette corpus in-repo
  • analyze first-slot and first-four-slot patterns
  • study exact and near duplicates
  • run Leonardo-style prefix analysis to see how palettes degrade as colors are added
  • identify The Economist and Apache ECharts as leading structural references

Phase 3: directed DFT candidate engineering

This phase produced Candidate E and its refinements:

  • test several new DFT category-10 candidates
  • focus hardest on positions 1–5
  • keep the second cool blue-family color
  • probe slot 4, then slot 8, then slot 10
  • promote moss and softer charcoal into the stable tail

Artifact Preservation

Current palette-analysis assets live in:

  • repo path: docs/docs/guides/color-palettes-assets/

Historical snapshots are preserved in:

  • canonical docs live under docs/docs/guides/
  • canonical PNG/CSV/PDF assets live under docs/docs/guides/color-palettes-assets/

Important preserved PNGs include:

Additional preserved analysis tables include:

The category-10-electric-cdef-analysis pair preserves a later comparison pass across the electric c/d/e/f variants. It is part of the historical artifact trail for palette development rather than the canonical live palette spec.

In practice, the history snapshot now preserves most of the active palette engineering asset set, including:

  • reference corpus analysis outputs
  • case-study outputs
  • candidate-comparison outputs
  • microround and slot-probe outputs
  • full-palette Candidate E views
  • current named/degradation views

Key Decisions Preserved

  • The palette stayed blue-led.
  • The earlier blue / gold / green / lilac ... palette is part of the same design story and remains preserved.
  • The team chose to keep a second cool blue-family color early rather than forcing a warm second slot.
  • The Economist and Apache ECharts emerged as the most instructive structural references, even though DFT did not want to copy their bright-red behavior.
  • The first five positions became the primary optimization target rather than treating all ten slots as equally critical.
  • Slot 8 moved from darker olive to moss.
  • Slot 10 was softened from a darker charcoal to #56616f.
  • Earlier palette directions are retained in the history snapshot rather than being overwritten.

Preservation Rules

When iterating again later:

  • update the canonical live docs and config only after a palette is considered stable
  • preserve interim PNGs, CSVs, and notes in the dated history folders
  • preserve both major palette phases, not just the latest stable state
  • prefer adding new current artifacts rather than overwriting older ones
  • treat history notes as snapshots, not as files to retroactively rewrite
  • repo path: ai_notes/considerations/DFT_CATEGORY_10_PALETTE_SELECTION_2026.md