🟪 Constant (jov)

"Constant (jov)" is the legacy name for Jovimetrix's solid-color generator - the node that makes a flat image of any size and any color, with a mask output to go with it. The lowercase "(jov)" dates it to before the pack's 2.0 renaming pass, when it became CONSTANT (JOV) 🟪 with a color-picker-style VEC4 input. If a shared workflow references the old name and ComfyUI flags it missing, the current pack installs the renamed node - you just rewire the two ends, since the README warns renames don't migrate connections.

What it does

A solid color rectangle, sized to order:

• width / height (INT, default 256, 32–8192) - the canvas size.
• R, G, B (FLOAT, 0–1, default 1) - the color, as 0–1 floats. All 1 is white; (1, 0, 0) is red; (0, 0, 0) is black. Note these are floats, not 0–255, which trips people up if they're used to the modern node's 0–255 VEC4 color input.

Outputs are image and mask - the mask being a fully-white matte the size of the canvas, ready to drive compositing.

Why a solid-color node exists

Every compositor eventually needs a flat background. Common uses: a solid backdrop to composite onto, a matte for COLOR MATCH or BLEND operations, a "blank" image of a known size to seed a workflow or force a resolution, or a test card while debugging. It sounds trivial until you realize ComfyUI's core doesn't ship a "make me a 1024×1024 red rectangle" node - packs like this exist partly to fill exactly those gaps.

Installing it

Part of Jovimetrix:

• ComfyUI Manager - search "Jovimetrix", install.
• Manual - git clone https://github.com/Amorano/Jovimetrix.git into custom_nodes/, then pip install -r requirements.txt.

No models. Dependencies: numpy, OpenCV, Pillow, matplotlib, cozy_comfyui. Needs ComfyUI 0.1.3+.

The honest take

There's not much depth here, which is fine - a constant generator is a utility, not a feature. The two things worth remembering: the R/G/B values are 0–1 floats (enter 0.5 for mid-gray, not 128), and the modern CONSTANT (JOV) 🟪 adds a VEC4 color input with a real picker plus an optional image/mask input so you can matte a selected color onto an existing image. If you're building new work, use the modern node and its color picker; if you're just repairing an old workflow, this legacy version does the same job with three sliders. Don't overthink it - it's the boring node that makes the interesting ones possible.