Superside Crystal Upscaler (portrait detail)

There are two different jobs hiding under the word "upscale," and the KB's advice is to decide which one you have before you install anything. "More pixels" is a resize - Lanczos or an ESRGAN model, instant, free, can't hallucinate. "More detail" is a generative pass - a model inventing detail that was never there. This node is firmly the second kind, and it's specialized: it runs Clarity AI's Crystal upscaler on fal (fal-ai/crystal-upscaler), a portrait- and facial-detail-focused upscaler, and it exists to solve a specific pipeline problem rather than to be your general 4x upscaler.

The pipeline problem, stated plainly by the pack's own source: the generative inpaint node this is meant to follow (the Z-Image Turbo inpaint, used for re-skin work) has a real ceiling around ~2048px on its longest edge. Ask the generator for a bigger image and you don't get more detail - the endpoint silently falls back to a fixed square. So once generation is at that ceiling, "more detail" can't come from the generator; it has to come from a dedicated upscale pass on the result. That's this node's job: it sits after the generative inpaint and before you resize back to the original resolution, adding a portrait-aware detail jump (2x by default) so the final plain Lanczos stretch back to the true original covers a smaller gap and looks far sharper than a single ~2.3x interpolation would.

Inputs are image and api_key, with three optional knobs:

• scale_factor - 1 to 4, default 2. How much to upscale before the final resize-to-original step. 2 is the sensible default; going to 4 is where you pay more and start to invite artifacts.
• creativity - 0 to 1, default 0. How much the upscaler is allowed to invent vs. stay literal. At 0 it's a faithful detail restorer; as you raise it, it enhances more aggressively and starts rewriting texture. For faces, the default is where most people want to stay.
• output_format - png or jpg.

Outputs are image (IMAGE) and info (STRING, the fal result URL).

The honest framing on when to use it: this is a face/portrait-detail upscaler, not a general-purpose one, and it's an API call (metered fal credits, your image leaves the machine). If you're upscaling a landscape or a clean product shot where the detail is already there, you're better off with a free local ESRGAN - the KB's table has your back there. This node earns its keep in exactly the pipeline it was built for: portrait re-skin/retouch work where you generated at ~2K, want real added facial detail, and don't want the final resize to your original high-res file to look soft. Community signal on "Crystal upscaler" is almost nonexistent - nobody's trading tips about it - which matches its role as a production-internal tool made public.

Install - ComfyUI Manager (search "comfyui-superside-nodes") or:

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

Restart ComfyUI, find it under Superside. Paste your fal key into api_key (blank falls back to FAL_KEY, both blank errors). No model files to download - the pack's only real dependency is fal-client.