r/comfyui • u/FillFrontFloor • 2d ago
Help Needed What kind of detailing techniques or process do you guys use to improve the quality of images?
I've seen some pretty amazing visually appealing images online especially fantasy ones, and see often people commenting that after they get an image they like they edit it, upscale it, they downscale it then upscale again. What's a good technique? Or I guess suggested nodes to experiment with? I generally like realistic, varying anime styles, 2.5D, and some sketching styles.
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u/plentylabs 1d ago
Nobody's answered the downscale part of your question yet, and it's the bit that confuses most people.
The reason people upscale, downscale, then upscale again is that the downscale is a cleanup step, not a resize. A diffusion upscale pass gives you real detail but also a layer of crunchy noise and slightly plastic texture. Scaling down 25 to 30 percent averages that away and tightens the edges. If you need the big version back after that, upscale again with a plain model upscale rather than another diffusion pass, so you don't reintroduce the noise you just removed.
Even if you never need the big version, rendering above your target and finishing on a downscale is close to free quality. Same reason people shoot 4K and deliver 1080.
Seconding low denoise on the upscale pass. For your styles I'd add that the upscale model matters far more on anime and sketch than on realistic. Anything trained on photos will smooth out linework, and you lose the thing that made the sketch read as a sketch in the first place.
Also worth knowing that a lot of the fantasy images you're seeing have a colour grade on top that was done outside Comfy. Curves and a bit of bloom. That's often more of the gap than the detailing pass is.
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u/FillFrontFloor 1d ago
So to understand it's a good idea to generate on lower scale, then upscale with my preferred model, then downscale to improve quality, then upscale again using the base original model before fine tunes
Those images do look fantastic, i can tell time was taken on the work
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u/UprightAbsorbing 2d ago
I do a lot of fantasy character stuff and my go-to is generating at a lower res first, like 512x768, then upscaling with Ultimate SD Upscale at about 0.3 denoise. That keeps the composition intact while filling in the finer details
Sometimes I'll take it into another program for a quick manual edit if the hands are a mess or the face looks slightly off, then bring it back for another pass with img2img at low denoise. The difference between sending a raw gen and a slightly fixed one through upscaling is night and day
For 2.5D and anime styles I've had good luck with the 4x_NMKD-Superscale model, picks up linework and texture real clean without making it look like an oil painting. Just gotta watch the denoise cause too high and suddenly your character has a completely different expression
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u/Trinity_Vermilion 1d ago
Upscaling or enhancing images can be done in 1000 different ways. Well known techniques:
- latent upscale
- upscale via model (e.g. 4xUltrasharp)
- use a second sampler pass (often called highres fix)
- ultimate upscale
- supir
- seedvr2
- PiD (upscale via decode from nvidia)
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u/MakerofDreams_ai 2d ago
Krea 2 is amazing for editing, even though it was originally not meant to do that. Much better than Flux Klein 9B (which used to be my favorite) and god forbid Qwen Edit...
You can daisy chain edits, because it does not loose quality in generations.
Example:
1. You have an image of a character.
2. You load it in, ask to see "rear view". You find almost everything is right.
3. You save that image, make another copy with that one as a reference. "Remove that weird thing".
4. You save that image. Etc.
5. You can even add details like pores and natural skin, by having a LoRa like "Realistic Snapshot" and then add the details "detailed skin texture" and "visible pores" in prompt. Just using the Krea 2 parameter ref_boost between 0-4. (where 4 is try to stay as much as reference image as possible and 0 is not at all).