1 The idea
The sparks here reach about 62. With plain sRGB everything above 1 clips to white. A view transform (ACES, AgX, Filmic, …) is a curve applied when displaying, squeezing the bright range so detail survives.
Important: the view transform lives in the viewer and at export, as the pipeline says. It does not go into the comp maths; the linear values inside stay the same.
2 Hands-on
Raise the exposure and flip between the two modes
3 Deep dive
Scene data vs a picture for a screen
The comp holds light from 0 to 70 and beyond, but a screen shows a limited range. A view transform maps scene light to a picture for that screen. Plain sRGB is a view transform too, one with a hard cut at 1.
ACES output transforms, AgX and Filmic roll the highlights off gradually and move very bright colours toward white, closer to film or a real camera.
- 1Scene-linear comp
- 2View transform
- 3Screen: sRGB / Rec.709 / HDR
Same comp, different looks
Everything you judge by eye, such as fire colour, highlight detail or glow strength, depends on the view transform you look through.
| view | Above 1 | Where you meet it |
|---|---|---|
| plain sRGB | hard clip at 1 | Nuke’s sRGB Viewer (nuke-default config) |
| ACES output transform | soft roll-off with its own contrast | ACES pipelines in Nuke, Resolve |
| Filmic | soft roll-off, contrast chosen by Look | Blender before 4.0 |
| AgX | soft roll-off, bright colours drift to white | Blender 4.x (default) |
Every department must look through the same one
If lighting judges the render through AgX in Blender while comp looks through plain sRGB in Nuke, the same image looks very different with identical numbers, and everyone keeps “fixing” each other.
Sparks at about 62: through plain sRGB they are flat white blobs; through a roll-off view you see a white core grading into orange. Before starting, ask which config and view the show uses.
Review files vs deliveries
EXR deliveries are normally linear with no view transform, because the next person needs real data. Review MOVs or JPEGs need the view transform baked in exactly once.
Bake it twice and the image looks washed out: shadows and mids lift (an extra sRGB encode turns 0.1 into about 0.35). Forget it and the linear data looks dark and contrasty, with clipped highlights.
- 1Comp (linear)
- 2Delivery EXR: no view
- 3OCIODisplay → Write (raw)
- 4Review MOV
Compare one review file with the Viewer per show; if they differ, a transform is doubled (washed out) or missing (dark and contrasty)
4 In real work
In Nuke
- Project Settings > Color: set OCIO and the show’s config; the Viewer’s display/view menu then lists that config’s views.
- Viewer: the view transform is applied after the image; sampled values stay scene values, so sparks at 62 still read 62.
- OCIODisplay: bakes a display/view into the image for a review file; follow it with a Write with raw data ticked so it does not convert again.
- Delivery EXR Write: linear or the working space, no view transform.
- Never put OCIODisplay or a tone curve upstream of merges in the comp; keep it at the end of a review branch.
Common mistakes → the fix
- ✗ Baking the view transform into a precomp or delivery EXR✓ The next artist applies it again. Keep EXRs linear.
- ✗ OCIODisplay followed by a Write that converts again✓ Tick raw data on the Write so it converts only once.
- ✗ Grading fire colour under plain sRGB, then switching to the show’s view✓ The orange will not be what you intended. Judge under the show’s view from the start.
- ✗ Clamping highlights at 1 because “the Viewer clips anyway”✓ Glows, motion blur and defocus need those values above 1. Keep them.
- ✗ AgX in Blender, plain sRGB in Nuke✓ Agree on one view across every department.
Before you send the shot
- You know the show’s config and view, and the Viewer uses them
- No view transform or tone curve inside the comp graph
- Delivery EXRs are linear with values above 1 intact
- Review files have the view transform exactly once and match the Viewer
5 Check yourself
Where does the view transform belong?
🔒 Answer the question above and this card opens
1. Sparks at about 62 look like flat white blobs in the Viewer. What do you check first?
2. A review MOV looks washed out and brighter than the Viewer. Most likely cause?
Where the numbers come from: Curves and matrices are computed from published definitions (sRGB IEC 61966-2-1, ARRI LogC3 EI 800, Rec.709/P3/Rec.2020/ACES AP1 primaries) and checked against published reference numbers. The tone curve is an example formula, not ACES/AgX/Filmic.