Color space without gamma curve — raw sensor data. Essential for grading and compositing where every mathematical operation must be linear.
Anyone working on a Digital Intermediate or compositing VFX plates in Nuke will quickly encounter the core problem: your sensor data is available, but the monitor already displays it in a shaped form. The gamma curve — this non-linear brightness compression — is made for the human eye, not for mathematical operations. Linear encoding bypasses exactly this. It stores color values as the sensor captured them — raw, unadulterated, without that S-curve that has shaped television standards for decades.
In practice, this means you work in a linear color space, where brightness values are proportional to the actual amount of light. A pixel with a value of 0.5 is exactly half as bright as one with 1.0 — not optically, but measurably. This sounds academic, but it's essential for every compositing step. When you perform keying, color correction, or rotoscope operations, you're working with raw data. Blur filters, grain addition, even simple multiplications — all these computational steps only yield physically correct results when the underlying values are linear. If you do this in gamma space, you'll get visual errors: duller transitions, incorrect glows, distorted color blends.
On set, linear encoding is achieved by shooting in RAW format or setting your camera to a log profile — such as CinematonicLUT, REDlogfilm, or Sony S-Log. These intermediate encodings are closer to linear than standard gamma curves. In the post-workflow, you then decode to true linear — for example, in DaVinci Resolve or Nuke — and only then apply your color corrections. The final output is then gamma-encoded again for the monitor, but the creative and technical process in between lives in linear space.
The subtle detail: there are different linear color spaces — Rec.709 Linear, ACEScg, DCI-P3 Linear — depending on the target medium. But the principle remains: you work without gamma distortion. Those who ignore this and composite directly in sRGB or Rec.709 (gamma-corrected) will struggle with color casts and unwanted brightness jumps. The best VFX supervisors write it into the brief: "All plates linear, all comps in linear color space." This saves you days of troubleshooting later.