FEColorOut

ComfyUI doesn't have a first-class "color" type in core, so custom packs invent their own. This one's is called RGB_COLOR, and FEColorOut is how you create one by hand. Three integer sliders - red, green, blue, each 0–255 - and one color output on the other side. That's it.

The reason this exists is that the pack's color-aware nodes, like FEColor2Image and the image-padding nodes, want a color as a single dict value ({r, g, b, s}) rather than three loose wires. FEColorOut is the convenient way to produce that: wire its output straight into a color-typed input and you've got a solid fill color without wrangling the dict by hand.

The s in that dict is a seed, and it's the one subtle piece here. The value is always -1 out of FEColorOut, which signals "no randomization." But the color format the pack uses also supports ranges - a color where a channel is [min, max] instead of a single number - and a non-negative seed that drives per-batch randomization in FEColor2Image. FEColorOut doesn't do ranges; for that you want the sibling node FERandomizedColorOut (also in this pack). If all you need is a boring, predictable color, this is the one.

Worth noting: FEColorOut has no other inputs and no knobs beyond the three sliders. It's a leaf node - you don't feed anything into it, and its output is the only thing that matters. If you need a color to bake into a padded outpaint border or a test image, it's the cleanest way to get there.

One practical gotcha with custom types like RGB_COLOR: because it's not a core ComfyUI type, the node's color widget is whatever the pack's frontend gives you, and mismatched connections between packs that happen to define a different "color" type will look connectable thanks to the *-typed sockets this pack uses, but the receiving node may not understand the value. Keep FEColorOut feeding this pack's own color inputs and you're fine. It's a small node, honestly, but it's the piece that makes the rest of the color machinery usable.