color-science

name	color-science
description	LUTs, white-balance, mood-driven grading, and color-space deliverable mapping. Helios uses this to brief comfyui and color sub-pipelines.
user-invocable	false
argument-hint	<grade|lut|deliverable-map>
allowed-tools	["Read"]

Color Science

The color-grading and color-management reference. Helios uses it to translate a mood slot in a ShotList into concrete LUT choices, white-balance, and a deliverable color space.

Purpose

Ensure every render leaves the studio in the correct color space for its destination, carries a consistent mood-driven grade, and survives the round-trip from generation -> grade -> compression -> playback.

When to use

• Helios is assembling a ShotList and needs to populate lighting_notes and grade intent per shot.
• A render is about to be exported and the deliverable channel needs a specific color space.
• A campaign spans multiple channels and grade consistency must be enforced across cuts.
• Picking a reference LUT or building a custom grade for a new mood.

Inputs

• mood keyword (from controlled vocab below)
• Source render color space (typically linear or Rec.709 from comfyui)
• Destination channel(s) from CreativeBrief.channels

Outputs

• A grade brief: {primary_lut, white_balance_k, tint, contrast_curve, saturation, highlight_rolloff, shadow_lift, deliverable_color_space, deliverable_transfer}
• A delivery profile per channel

Color-space deliverable mapping

Channel	Color space	Transfer	Bit depth	Notes
Web / social (IG, TikTok, X, LinkedIn, Threads)	Rec.709	sRGB / gamma 2.2	8-bit	Convert from linear; clamp to legal range
YouTube SDR	Rec.709	BT.1886	8-bit	Upload h.264 high profile or VP9
YouTube HDR	Rec.2020	PQ (SMPTE ST 2084)	10-bit	HDR10 metadata required
Streaming HDR (Netflix-style)	Rec.2020	PQ or HLG	10-bit min	Per-stream metadata; consult deliverable spec
Theatrical / DCP	DCI-P3	gamma 2.6	12-bit XYZ	DCP is XYZ, but grade in P3
Broadcast SDR	Rec.709	BT.1886	10-bit	Legal levels mandatory; QC for chroma subsampling
Print / OOH	sRGB or Adobe RGB or CMYK	per print house	varies	Convert with soft-proof; ICC profile must match press
Email / web hero stills	sRGB	gamma 2.2	8-bit	Strip EXIF; embed sRGB profile

Rule: never deliver Rec.2020 to a Rec.709 endpoint without an explicit downconvert. Never assume a viewer's screen is calibrated.

White-balance reference

Light source	Kelvin	Tint bias
Candle / tungsten warm	2000-2700K	+magenta slight
Tungsten halogen	3200K	neutral
Fluorescent (varies)	3500-5000K	+green often
Daylight (noon)	5500-6000K	neutral
Overcast	6500-7500K	+blue
Shade / blue hour	8000-10000K	+cyan

Reference grades by mood

• neon-noir — WB 3200K, +magenta tint, crushed shadows, neon-saturated highlights (cyan + magenta), low overall saturation outside neon hues, hard contrast S-curve, halation on speculars. LUT family: cyber, blade-runner, miami-vice.
• golden-hour — WB 4200K, +amber tint, soft highlight rolloff, lifted shadows, warm saturation skew, mild bloom on sky and skin. LUT family: kodak-2383, fuji-3513, anamorphic-warm.
• clinical-clean — WB 5600K daylight neutral, no tint, high mid-tone contrast, full saturation but cool skin tones, zero halation, hard whites at 100 IRE. LUT family: medtech, apple-ad, scandi-minimal.
• gritty-doc — WB on-set as captured, slightly desaturated, lifted blacks, grain overlay, no rolloff, natural skin. LUT family: arri-logc-natural, news-rec709.
• pastel-dream — WB 5200K, +slight magenta, very low contrast, lifted blacks, lifted whites, heavy desaturation in greens/blues, milk-bath highlights. LUT family: wes-anderson, pastel-portrait.
• product-luxe — WB 4800K, neutral tint, deep blacks, controlled speculars, +saturation only in product-hue, vignette. LUT family: hero-product, watch-ad.
• moody-cinematic — WB 4000K, teal-orange complementary push, S-curve, controlled highlights, no clipping. LUT family: blockbuster-teal-orange, denis-villeneuve.
• broadcast-news — WB 5600K, no creative grade, legal-range only, +slight saturation on flesh. LUT family: rec709-legal.

How Helios uses this to brief comfyui

In the comfyui workflow brief (see comfyui-workflow-recipes), Helios populates:

• style_prompt snippets pulled from the mood entry (e.g. for neon-noir: "crushed shadows, neon magenta-cyan highlights, halation on speculars, anamorphic flare")
• negative_prompt to suppress unwanted shifts (e.g. "oversaturated greens, daylight balance, flat contrast")
• A post-render LUT application node if the workflow includes one (1D for tone, 3D for full grade)
• output_color_space matched to the destination channel

Procedure

1. Read the ShotList shot's mood (or infer from CreativeBrief.brand_constraints.tone).
2. Look up the mood entry above; copy WB, tint, contrast, saturation, LUT family into the grade brief.
3. Determine destination channel(s) from CreativeBrief.channels; pick deliverable_color_space and deliverable_transfer from the mapping.
4. Attach the grade brief to the AssetJob payload for the shot.
5. After render, verify: scopes within legal range, no clipping above 100 IRE for broadcast, embedded ICC/transfer matches deliverable spec.
6. Log grade decisions to eights.memory.remember(domain="creative", scopes=["public"], tags=["color","grade"]) for future recall.

Failure modes / escalation

• Mood not in vocab — propose a new entry; HITL approves before first use; log to procedural resources (low-risk, auto-evolve).
• Channel needs HDR but source pipeline is SDR — escalate; HDR requires a different generation/grade pipeline.
• Mixed-channel campaign with conflicting grades — produce a master grade in the highest gamut (Rec.2020 / P3) and derive SDR trims; document trims in RLM/output/photo/.

References

• ITU-R BT.709, BT.2020, BT.1886; SMPTE ST 2084; ISO 22028.
• comfyui workflow recipes: comfyui-workflow-recipes