Real-ESRGAN Upscale (Replicate)

Let me save you some money before anything else: Real-ESRGAN is the one node in the Replicate Select pack you probably shouldn't be paying for. It's a classic ESRGAN-family upscaler - the "more pixels" kind, not the "invent new detail" kind. It takes a sharp image and makes it bigger, adds no new content, cannot hallucinate. Locally that's a handful of milliseconds per image, on any GPU worth owning, with a model file measured in megabytes.

So who is this node actually for? People who want the convenience without a local GPU at all - a cloud-rendered workflow where every step already leaves the machine. If that's you, welcome, it works. If you have a working ComfyUI install and a GPU, this is a paid version of something you already get free with a small model download, and the honest advice is to skip it.

How it works

The mechanism is the pack standard: Replicate_cjwbw_real_esrgan wraps cjwbw/real-esrgan on Replicate, uploads your image as PNG, runs the upscale server-side, downloads the result, and hands you back an IMAGE tensor. The type is IMAGE so it drops straight into SaveImage, or into a chain that feeds an even bigger pipeline.

That matters for why you'd wire it in at all: it slots between a local generator and your final save with zero restructuring. In a graph that's already calling cloud nodes for generation, one more per-call step is just the cost of doing business.

The inputs (both of them)

This is the thinnest node in the pack, which is refreshing.

• image (required) - the IMAGE tensor to upscale.
• upscale - factor, 2, 4 (default), or 8. That's it.

Output: image, an IMAGE tensor.

There's no detail knob, no tile size, no denoise. If you want that, you're describing SUPIR or a tiled workflow, not Real-ESRGAN. The single choice you actually have is how big, and 4x is the sane default - 8x on a non-generative model mostly means "larger and softer," not "more detail."

Install

This is a member of Replicate Select, so install the pack once and every node arrives together:

cd ComfyUI/custom_nodes
git clone https://github.com/Pharma-Lobby/ComfyUI-Replicate-Select

Or ComfyUI Manager → Install Custom Nodes → "Replicate Select", then restart. The dependency is just replicate>=1.0.7. Auth is an environment variable, not a field in the node:

export REPLICATE_API_TOKEN=r8_...

The take

If you're on the fence: the local ESRGAN route (RealESRGAN x4plus, or community favorites like 4x-UltraSharp) is free, instant, and has no per-call meter - and contrary to what you'd guess, the cheap rung is gaining share in the community, not losing it, because for clean sources it's genuinely the right tool. Reach for this node only when the rest of your workflow is already cloud-bound. In that world it's a perfectly good, boring, dependable pixel-stretcher.