Nuke Ramp

Every proper compositing app ships a ramp generator, and for good reason: a smooth gradient is the single best tool for finding out what your pipeline is doing to color. NukeRamp brings that to ComfyUI - it generates horizontal, vertical, radial, diagonal, and checkerboard patterns from a start color to an end color, at any size, in a batch. It's a test-pattern node, and it knows it.

Reach for it when you need to prove something about your graph rather than make a pretty picture. A horizontal ramp run through your VAE encode/decode will instantly expose banding. A ramp through a color transform shows you exactly where the curve pushes mids. Feed a radial ramp into a ControlNet depth preprocessor and you can sanity-check that the model reads gradients as gradients. And if you're tuning a sampler's effect on exposure, ramps are a lot easier to reason about than a busy generated image.

How it works

The node builds a coordinate grid - x from 0 to 1 across the width, y down the height - and maps it to a ramp, then lerps between color_start and color_end pixel by pixel. Radial ramps measure distance from the center normalized to the corner, so the end color shows up at the corners. Checkerboard is an 8×8 grid of alternating tiles. Every output gets a solid alpha of 1 and gets clamped to 0–1.

Colors are passed as comma-separated strings of three values in 0–1 range: "0,0,0" for black, "1,1,1" for white. If parsing fails, it silently falls back to a black→white ramp rather than erroring - handy in a pinch, mildly annoying when you fat-finger a color and wonder why the gradient changed.

The inputs that matter

• width / height - 64 to 4096, default 512 each.
• ramp_type - horizontal, vertical, radial, diagonal, or checkerboard.
• color_start / color_end - "R,G,B" strings in 0–1 space.
• invert - flips the ramp direction (white to black instead of black to white).
• batch_size - how many identical frames to emit, up to 64. Handy for feeding a multi-frame video pipeline a known constant test input.

Output is a single IMAGE (RGBA, batch size frames).

Installing it

NukeRamp ships in the Nuke Nodes pack. Manager: search "Nuke Nodes" and install. Or:

cd ComfyUI/custom_nodes
git clone https://github.com/sumitchatterjee13/nuke-nodes-comfyui.git nuke-nodes
cd nuke-nodes
pip install -r requirements.txt

Restart, then find it under Add Node → Nuke → Viewer. No dependencies beyond the pack's own (numpy/torch are already ComfyUI's), no models.

Gotchas

• Colors are 0–1, not 0–255. "255,255,255" parses into three values way above 1 and everything clamps to white. Use "1,1,1".
• The fallback is silent. If you typo a color string, you get black→white, not an error. If your ramp "forgot" your colors, check the strings first.
• Radial ramps reach the end color at the corners, not just the edges - that's deliberate, matching the corner distance normalization. If you wanted a soft vignette shape, this is the wrong tool.
• The pack is a small, young project with no real community presence yet - so when something's odd, the source (viewer_nodes.py) is short and readable. Don't go hunting for forum threads; there aren't any.