线性色彩空间与色彩管理Linear Color Space

难度LEVELL3 · 高级L3 · Advanced 领域TOPIC视觉特效

先学：Prerequisites: 色彩管理

学习目标LEARNING OBJECTIVES

学完你能说清 Fusion 合成为什么要求线性色彩空间（Linear Color Space），认出非线性计算的典型症状，并让项目色彩管理替你管好转换。

概念说明CONCEPTS

线性色彩空间（Linear Color Space）是"像素数值与真实光强成正比"的计算环境——Fusion 的叠图、模糊、抠像全都按这个假设设计；拿伽马编码的素材直接算，数学上就错了。

  • 显示伽马不是线性：为显示优化的素材（如 Rec.709）做过伽马（gamma）编码，数值与光强不成正比——数值一半，亮度并不是一半。
  • 非线性的数学会露馅：在伽马值上直接混合、模糊或抠像，会出现边缘发暗、叠图发脏、抠像带黑边——不是操作错，是数值空间错。
  • Fusion 期望线性输入：合成里的叠加、模糊、键控都按线性光设计，线性空间里两个 50% 亮度相加才真的等于 100%。
  • 色彩管理自动转换：项目开启色彩管理后，Resolve 会在图像进出 Fusion 时自动处理线性转换，你不用逐节点操心（开启方法见 色彩管理）。
  • 什么项目最该在意：纯 Rec.709 的 SDR 小项目问题常不显眼；一旦混用 Log、HDR 素材或做精细合成，不开管理就会在边缘和混合处露馅。

操作步骤STEPS

  1. 点右下角 Project Settings，打开 Color Management 类别
  2. 把 Color Science 设为 DaVinci YRGB Color Managed，点 Save（原理回顾见 色彩管理）项目设置里的色彩科学选项
  3. 进 Fusion 页面做个简单合成：用文字或图形经 Merge 叠到实拍素材上
  4. 放大查看叠加边缘与半透明区域，确认没有发暗的边放大检查合成边缘

练习PRACTICE

  1. 同一组合成在色彩管理开、关两种状态下各截一张图，对比边缘差异，用一句话说出原因。
  2. 拿一条 Log 素材进 Fusion 做叠加，先看不开管理时的灰和暗边，再开启管理对比修复效果。

常见问题FAQ

合成边缘有一圈黑边，是我抠像没抠干净吗？

多半不是操作问题，而是在伽马编码的数值上直接计算了。开启项目色彩管理让 Fusion 在线性空间合成，黑边通常自己就消失了。

普通的 Rec.709 项目也要管这个吗？

小项目里影响常常看不出来，可以暂时不纠结。但只要混用 Log/HDR 素材或做精细合成，就必须开色彩管理。

开了色彩管理，调色思路要变吗？

不用变。管理只统一计算的起点和空间，调色照样在节点里做；基础概念见 色彩管理。

线性色彩空间要我逐节点手动设置吗？

不用。项目级色彩管理开启后，进出 Fusion 的转换由 Resolve 自动处理，你要做的只是确认设置已打开。

Learning Objectives学习目标

After this card you can explain why Fusion compositing expects a Linear Color Space, recognize the classic symptoms of non-linear math, and let project color management handle the conversions for you.

Concepts概念说明

A Linear Color Space is a computing environment where pixel values stay proportional to real light intensity — Fusion's layering, blurring and keying are all designed around that assumption; run the math on gamma-encoded media and it comes out wrong.

  • Display gamma is not linear: media optimized for display (like Rec.709) is gamma-encoded, so values are not proportional to light — half the value is not half the brightness.
  • Non-linear math shows: blend, blur or key on gamma values and you get darkened edges, muddy overlays and black key fringes — not an operator error, a wrong number space.
  • Fusion expects linear input: over-operations, blurs and keyers are built for linear light; only in linear space do two 50% lights truly add up to 100%.
  • Color management converts for you: with project color management on, Resolve handles the linear conversion as images move in and out of Fusion — no per-node chores (setup in Color Management).
  • When it matters most: an all-Rec.709 SDR mini-project often hides the problem; mix in log or HDR media, or do precise compositing, and skipping management shows up at edges and blends.

Steps操作步骤

  1. Click Project Settings in the lower-right corner and open the Color Management category
  2. Set Color Science to DaVinci YRGB Color Managed and click Save (recap the theory in Color Management)The Color Science option in Project Settings
  3. Jump to the Fusion page and build a simple composite: layer text or a graphic over camera footage with Merge
  4. Zoom into the layered edges and semi-transparent areas, and confirm nothing darkensZooming in to check composite edges

Practice练习

  1. Screenshot the same composite with color management off and on, compare the edges, and explain the difference in one sentence.
  2. Bring a log clip into Fusion for layering: first look at the flat, dark-edged result without management, then switch it on and compare.

FAQ常见问题

A black ring around my composite — didn't I key cleanly?

Probably not an operation problem at all: the math ran on gamma-encoded values. Turn on project color management so Fusion composites in linear space — the fringe usually vanishes on its own.

Do plain Rec.709 projects need to care?

In small projects the difference often stays invisible, so it can wait. But the moment you mix log/HDR media or composite precisely, color management is a must.

Does grading change once management is on?

No. Management only unifies the starting point and the working space; your grading still happens in nodes — see Color Management for the basics.

Do I have to set linear space node by node?

No. Once project-level color management is on, Resolve handles the conversions in and out of Fusion automatically — your only job is confirming the setting is on.

深度资料：线性色彩空间与色彩管理 →Deep dive: 线性色彩空间与色彩管理 →

本卡术语Terms in this card

色彩管理Color Management 色彩空间Color Space Gamma（中间调）Gamma 调色Grade 静帧Still 项目设置Project Settings 模糊Blur 合成Compositing Fusion 合成Fusion 合并Merge 节点Node