WAS LUT Blender

If you've got two color grading LUTs and want something in between them - say, a warm look and a cool one, blended toward a custom middle ground - this node builds that as its own reusable LUT, instead of you chaining two WAS Apply LUT nodes and hoping the sequential result looks like a true blend. It doesn't touch an image at all; it produces a LUT that you apply afterward.

How it works

Feed it two LUTs (lut_a, lut_b) and it merges them into one new LUT according to mode and strength. The eleven blend modes split into a few families worth knowing apart: hsv, lab, and oklab blend in perceptual color spaces rather than raw RGB, which generally produces smoother, more natural-looking transitions between two grades - oklab is a reasonable default if you're not sure which to pick. linear, cosine, smoothstep, and slerp are different interpolation curves over the raw color values. multiply, screen, and overlay are the same classic Photoshop-style blend modes you'd recognize from image editing, applied here to combine two LUTs instead of two images. auto lets the node pick for you.

output_size sets the resulting LUT's cube dimension - 33 is the standard size used across most professional grading tools, and the default for a reason; only change it if something downstream specifically expects a different resolution.

The inputs and outputs that matter

• lut_a / lut_b (LUT) - the two LUTs to combine. Both need to come from an upstream WAS Load LUT node (or another LUT Blender, if you want to chain blends).
• mode - pick a perceptual mode (hsv/lab/oklab) for a smooth blend between two genuinely different looks, or a Photoshop-style mode (multiply/screen/overlay) if you specifically want that kind of combination effect rather than an in-between grade.
• strength (default 0.5, range 0–1) - how far toward lut_b the blend leans; 0.5 is an even split.
• output_size (default 33, range 17–65, odd values only) - the combined LUT's resolution. Leave at 33 unless you have a specific reason not to.

Single output: lut - feed it into WAS Apply LUT (or WAS Save LUT if you want to export it as a .cube file) to actually see or use the result.

How to install it

Via ComfyUI Manager: search "WAS_Extras", install, restart. Manually:

cd ComfyUI/custom_nodes
git clone https://github.com/WASasquatch/WAS_Extras

Restart ComfyUI. No extra dependencies.

Common issues & troubleshooting

This node runs but nothing visibly changes. That's expected - it outputs a LUT, not an IMAGE. It has no visible effect on its own; you need WAS Apply LUT downstream before you'll see anything.

Blend looks harsh or posterized at the transition. Try switching mode to one of the perceptual options (oklab, lab, or hsv) instead of a raw RGB interpolation mode - blending two very different grades in straight RGB space is where banding and odd color shifts tend to show up.

Combining two LUTs doesn't look like "halfway between them" when applied. Check strength first (0.5 should be an even split), but also remember that different modes genuinely produce different results at the same strength - multiply/screen/overlay aren't designed to feel like a straight average the way linear or oklab are.

Downstream tool rejects the exported LUT. Check output_size - some external tools expect a specific cube dimension. 33 is the safest default if you're unsure what the target expects.