Gamut Node

Gamut handles two related operations:

1. Gamut conversion (e.g. Rec.709 → sRGB, DCI-P3 → Rec.2020) - a change of primaries.
2. Adding/removing gamma (e.g. Rec.709 gamma 2.4 → Linear) - a change of transfer function.

Used as a sandwich around a grading chain: a first Gamut linearizes the input, the color correction nodes work in linear (mathematically cleaner), and a second Gamut reapplies the output gamma before the Saver.

• Effects Library: Tools > Color > Gamut
• Quick add: right-click in the Node Editor → Add Tool > Color > Gamut

• Input (orange) - required. The 2D image to convert.
• Effect Mask (blue) - optional. Limits the conversion to an area.

A typical sandwich workflow for grading in linear:

MediaIn (Rec.709) → Gamut (Source=Rec.709, Remove Gamma) → Color Corrector/Curves → Gamut (Output=Rec.709, Add Gamma) → Saver

Between the two Gamut nodes, the image is linear - every correction happens in a mathematically clean space.

Source Space

Color space of the input. Set it based on where the image comes from (Rec.709 for HD broadcast, sRGB for the web, DCI-P3 for cinema, Linear for an already linear 3D render, etc.). Use No Change when you only want to add a gamma at the output.

Output Space

Color space of the output. Set it based on the target delivery. Typically Rec.709 for an HD broadcast master, DCI-P3 for a cinema film.

Remove Gamma (checkbox)

Check it on the first Gamut of the sandwich to linearize the input. Removes the gamma of the Source Space → the image is in linear space.

Add Gamma (checkbox)

Check it on the second Gamut to reapply the Output Space gamma before delivery.

Pre-Divide / Post-Multiply

Essential for premultiplied images (3D renders, keying, masks). Avoids halos on semi-transparent edges by dividing by the alpha before the conversion and multiplying again afterward.

• Rec.709 - the HDTV broadcast standard (the most common).
• sRGB - the web and standard screens. Close to Rec.709 but with a slightly different gamma.
• Rec.2020 - UHD / 4K broadcast, a wider gamut than Rec.709.
• DCI-P3 - digital cinema (SMPTE-431-2), used with DLP projectors.
• Linear - no gamma curve, scientific rendering. The basis of the pro cinema workflow.
• Cineon - 10-bit log film scan.
• Custom - manual definition through CIE 1931 (primaries, white point, gamma, limit, slope). See the dedicated section.

Color corrections in a non-linear space (Rec.709, sRGB) have a subtle flaw: the gamma curve distorts the math. A "50% image A + 50% image B" blend gives a wrong result in sRGB - you need to be in linear for the math to be right.

The full linear workflow:

1. MediaIn (Rec.709 source file)
   ↓
2. Gamut (Source=Rec.709, Output=Linear, Remove Gamma checked)
   ↓ (the image is now linear, the math is right)
3. Color Corrector, Curves, Merge, all the grading
   ↓
4. Gamut (Source=Linear, Output=Rec.709, Add Gamma checked)
   ↓ (back to Rec.709 for delivery)
5. Saver

In between, the image looks "washed out" in the viewer between the two Gamut nodes. Normal - linear space is not calibrated for SDR screens. The viewer can be set to apply a preview gamma automatically.

Custom mode lets you define a custom gamut through the CIE 1931 parameters:

• Primaries (R, G, B) - xy coordinates of the three primaries.
• White Point - white point (D65, D55, D50 depending on the standard).
• Gamma - exponent of the transfer function.
• Limit / Slope - to define non-standard curves (Cineon-like, linear with offset).

Rarely used, but essential to match an exotic color space or a specific broadcast pipeline.

Gamut (this node)

Simple, fast, direct control with sliders. Good for common conversions (Rec.709 ↔ Linear). Does not follow an OCIO config standard.

OCIO ColorSpace (and OCIO variants)

Based on OCIO configs (.ocio files shared between studios). Supports ACES, ACEScg, ARRI LogC, any pro pipeline. Requires an installed OCIO config.

Rule: Gamut for a standalone project or a simple workflow. OCIO as soon as there is a shared studio pipeline (cinema VFX, broadcast series).

• Grading in linear - a Rec.709 → Linear → grading → Rec.709 sandwich. The pro standard to avoid gamma artifacts.
• Matching a linear 3D render to a plate - the renderer outputs Linear, Gamut brings it back to Rec.709 before compositing with the plate.
• Conversion for cinema delivery - Rec.709 → DCI-P3 before export for cinema projection.
• Delinearizing an EXR for preview - load a linear EXR, Gamut Add Gamma in Rec.709 to view it correctly in the viewer.
• sRGB/Linear round-trip - a web image that needs mathematical processing, then re-export.

• Always Remove Gamma at the start, Add Gamma at the end - forgetting either side produces a visibly wrong render (too dark or too bright).
• A "washed out" image between the two Gamut nodes - that is normal, linear space is not calibrated for SDR display. Use the viewer's "View Gamma" option to compensate the preview without changing the flow.
• Pre-Divide for premultiplied images - a must on 3D renders and mattes in linear.
• No Change + Add Gamma - to apply just a gamma without changing the gamut (e.g. add a 2.2 gamma for preview).
• Blend modes in linear - adding two images in linear gives an energetically correct result, unlike Rec.709 where the addition is "too bright".
• For studio pipelines, OCIO is the standard. Gamut stays handy for quick work or freelance projects without an OCIO config.