comfyui-image-quality

name

comfyui-image-quality

description

Diagnose and fix image quality issues in a ComfyUI workflow — face/body color mismatch, AI-looking skin, broken hands, anatomy artifacts. Use when the user shares a generated image and asks to improve it, when they say it "looks AI-generated", when hands/eyes/skin look off, or when iterating on a workflow's output quality. Includes diagnostic checklist, ranked fix recipes with concrete settings that have been validated, and escalation paths.

ComfyUI Image Quality Skill

You are a senior ComfyUI workflow engineer helping the user improve generated image quality. Be concrete, propose minimal changes first, and verify each change actually helped before piling on more. Prefer modifying the user's existing open workflow (set_widget, add_node, connect_nodes) over rebuilding.

How to use this skill

1. Inspect — read the image (view_file) and the workflow (describe_graph). Diagnose what's actually wrong using the checklist below.
2. Pick the lowest-leverage recipe that addresses the issue. Don't pile on five fixes for one problem.
3. Apply via the live MCP — set_widget, add_node, connect_nodes (use connect_many for batches).
4. Verify — run_workflow, then compare_images([before, after]) or view_file on the new output.
5. Iterate — if the issue persists, escalate to the next tier. If a new issue appeared, often you went too aggressive and need to dial back.

Diagnostic checklist

When the user says an image "looks AI" or "is wrong", look for these specific tells in priority order:

Tell	What to look for	Most common cause
Face/body skin tone mismatch	Face skin warm/peachy while body skin reflects scene lighting (cool moonlight, neon, etc)	FaceDetailer running at high denoise on a tight crop loses the scene's color cast
Wrong finger count	Hand has 4 or 6 fingers, fused fingers, melted thumb	Base model couldn't render hands; FaceDetailer at low denoise (<0.5) just polishes the broken anatomy
Plastic/waxy skin	Glossy uniform skin with no pores or texture, gradient-like	Default samplers (especially euler) over-smooth on Illustrious/SDXL fine-tunes
Mirror-symmetric face	Eyes/eyebrows perfectly identical, doll-like	Default sampler + no asymmetry hints
Sterile background	Background looks like a render asset, no atmospheric variance	No film grain / chromatic aberration / depth
Over-detailed "transplanted" feature	A face/hand looks crisp while the surrounding body is softer	Detailer denoise too high (>0.6) creating a render-fidelity seam
Color drift across passes	Image shifts hue between samplers/upscalers	Missing color match between processing stages

Recipes (validated settings)

These are concrete settings that have been tested on real Illustrious/Pony workflows. Use them as starting points, then tune.

Recipe A — Face/body color mismatch

Symptom: face has different skin tone or lighting than the body. Most common when scene has strong color cast (moonlight, neon, sunset) and the face looks "neutral" / lit by a different lamp.

Fix layer 1 — Tune existing FaceDetailer:

• denoise: drop to 0.30 (was 0.45+). Preserves color grading; less freedom to repaint.
• bbox_crop_factor: raise to 4.0 (more shoulder/background in crop = lighting context for the model).
• feather: 35, noise_mask_feather: 30. Smoother blend boundary.
• wildcard (face-prompt-only): add scene-lighting tags. Don't use heavy weights — (1.2) triggers blotches.
  • Example for moonlit scene: cool blue moonlight on face, rim lighting, cyan ambient, soft shadow on cheek

Fix layer 2 — Add ColorMatchV2 (KJNodes): After the FaceDetailer, before any upscaler:

FaceDetailer.image → ColorMatchV2.target
VAEDecode.image    → ColorMatchV2.reference   (the pre-detailer body image as reference)

Settings: method: mvgd, strength: 0.5. Method mkl is more aggressive and can over-saturate; mvgd is the safe default. Strength >0.7 can introduce teal/blue cheek artifacts.

Recipe B — Hand artifacts (wrong finger count, melted hands)

Symptom: hand has 4 fingers, fused fingers, hand looks like dough, fingers too long.

The lever is denoise. Hand detailer at low denoise (<0.5) just polishes broken anatomy. Higher denoise gives the model freedom to rebuild structure.

Recipe — Hand FaceDetailer pass: Add after the face FaceDetailer (and any upscaler if one is in the pipeline):

• Node: FaceDetailer (Impact Pack)
• Detector: UltralyticsDetectorProvider with hand_yolov8s.pt
• Settings:
  • denoise: 0.50 (sweet spot — reconstructs anatomy but blends with body)
  • cycle: 1 (one pass — cycle 2 over-details and invents accessories like rings/tattoos)
  • bbox_crop_factor: 3.5
  • feather: 35, noise_mask_feather: 30
  • guide_size: 384 (raise to 512 only if hand is very small in frame)
  • cfg: 6
  • wildcard: keep MINIMAL — five_fingers, natural hand anatomy. Avoid:
    • slender_hand → makes fingers too long
    • detailed_fingernails → over-renders, creates "transplanted" look
    • Heavy weights (...:1.2) → trigger invented decorations (sigils, tattoos)

Don't go beyond 0.55 denoise unless you also fix the source prompt — at 0.7 the rebuilt hand looks transplanted (different render fidelity than surrounding skin).

Source-level fix (if base generation has bad hands): Add to base positive prompt: (perfect hands:1.1), well-defined fingers, anatomically correct hands, five fingers. Add to negative: extra fingers, fused fingers, missing fingers, deformed hands.

Recipe C — Anti-AI sheen (waxy skin, sterile look)

Symptom: skin looks like polished plastic; image feels too clean; reads as "AI generated" at a glance.

This is a stack of small wins, not one big fix. Apply in order; stop when good.

1. Sampler swap. Change KSampler from euler / euler_a to dpmpp_2m_sde + karras. Dramatically more organic shading and microtexture. ~Same speed. This is the single biggest "less AI" lever.
2. Add Film Grain (WAS Suite Image Film Grain or equivalent):
   • intensity: 0.08 (>0.15 starts darkening the image visibly)
   • protect_highlights: 1.0 (preserve bright areas)
3. Add Chromatic Aberration (WAS Suite or KJNodes):
   • intensity: 0.2 (subtle red/cyan fringe at edges)
   • At intensity >0.4 it becomes obvious distortion — keep low.
4. Negative prompt — anti-doll tags: smooth skin, plastic skin, airbrushed, doll, cgi, render, 3d, symmetric face, identical eyes.
5. Positive prompt — texture tags: detailed skin, skin texture, subsurface scattering, asymmetric eyes.

Pipeline order:

... → upscaler → film_grain → chromatic_aberration → save

Apply post-processing AFTER upscaling, never before (upscaling re-sharpens grain into noise).

Modern stack (validated on Krea 2 Turbo — bigger wins than the above):

1. Detail Daemon during sampling — ComfyUI-Detail-Daemon. The strongest texture lever now: it lowers noise-removal per step to add micro-detail without changing composition. Wire KSamplerSelect → DetailDaemonSamplerNode → SamplerCustomAdvanced (replaces the all-in-one KSampler; pair with BasicGuider for CFG~1 distilled models, BasicScheduler).
   • detail_amount: 0.5–0.6 default (Flux / Krea / Z-Image), 0.75 for pore-heavy portraits, stay under 0.85 (above that = over-sharpened/HDR crunch, itself an AI tell). SDXL: <0.25.
   • start 0.1, end 0.9. Tune by sweeping with batch_run(workflow=..., params_grid={"daemon.detail_amount":[0,0.25,0.5,0.75,1]}) + a labeled compare_images grid.
2. Optical-Realism depth-aware post-pass — ComfyUI-Optical-Realism. One physics node that replaces separate grain/CA/vignette: depth-of-field falloff, atmospheric haze, lifted blacks, highlight roll-off, halation, film grain, chromatic aberration. Needs a depth map: DepthAnythingV2Preprocessor (controlnet_aux) → its IMAGE into OpticalRealism.depth_map, original image into OpticalRealism.image.
   • Indoor/portrait starting point: haze_strength 0.12–0.2, dof_intensity 0.25–0.3, grain_power 0.03, lift_blacks 0.05, chromatic_aberration 0.002, highlight_rolloff 0.05. Landscapes take more haze.
   • When to apply — depth decides it (validated across scenes). The mechanic: the depth-aware DOF blurs only the far background. So:
     • Scene with a clear foreground subject + receding background (a table → a street, a person → a room): the blur lands on the background, the subject stays sharp and gains lens separation → apply the full pass. Big win even in flat overcast light — depth, not brightness, is what drives it.
     • Flat / top-down / subject-fills-the-frame scene (no background to recede): nothing for the DOF to blur, so the grain + global passes hit the subject and soften its micro-detail → skip it, or go subtle-only (DOF off, grain_power ~0.01, keep only warmth + highlight roll-off).
     • Bottom line: depth matters more than dynamic range, and the full stack is not always better than the generation alone. Flat, already-detail-rich output (especially Z-Image) is usually best left raw.
3. Prompt does ~70%. Pair with the prompt-krea2 "anti-AI realism mode" (or the prose prompt-* skill for the model): mundane unposed moment, named FLAT light, named worn surfaces, stacked real flaws, zero slop tokens.

Reusable templates live in the workflow library: run_workflow(path="utils/optical-realism-postpass.api.json") for the post-pass, and the generators run_workflow(path="krea2/krea2_t2i_detail-daemon.api.json") / run_workflow(path="zimage/zimage_t2i_detail-daemon.api.json"). Note: MarkdownNote is frontend-only — never put one in an API-format workflow (it breaks headless /prompt); use a sidecar .md instead.

Model pick (validated head-to-head, same prompt + Detail Daemon): for candid photo-realism Z-Image Turbo wins — documentary flatness + the strongest skin/hand micro-detail of the local models (and only 4 steps). Krea 2 renders moodier/more cinematic — pick it when you want an artful "photographer's photo" over a raw snapshot. Both beat Flux/Qwen/HiDream out of the box for this. Z-Image needs ModelSamplingAuraFlow(shift=3), EmptySD3LatentImage, the qwen_3_4b encoder (CLIPLoader type lumina2), and res_multistep/simple; prefer a GGUF/fp8 build over bf16 to cut its slow cold-load.

Recipe D — Pipeline simplification

Common antipattern: users have a KSamplerAdvanced split-stage setup (e.g. steps 0-20 / 20-30 with the same model on both halves). This is the SDXL base→refiner pattern misapplied — when both halves use the same model, you're just doing a single 30-step run with extra wiring.

Fix: replace the two KSamplerAdvanced nodes (and any PreviewBridgeLatent between them) with a single KSampler:

• Steps: sum of the original two stages (e.g., 30)
• CFG: same as before (6-7 typical for Illustrious)
• Sampler/scheduler: dpmpp_2m_sde + karras
• Denoise: 1.0

Same output, simpler graph, faster iteration.

Recipe E — Upscale path

Antipattern: 4x ESRGAN → full re-encode (VAEEncode) → KSampler refine → VAEDecode. VRAM-heavy at 4x; over-sharpens; takes ~2x as long as needed.

Fix: swap to UltimateSDUpscale (custom node):

• Tiles the image, runs SD denoise per 1024² tile, re-stitches with seam fix
• VRAM-friendly: same memory footprint regardless of total image size
• Settings: upscale_by: 2.0 (or 2.5 for wallpaper), upscale_model: 4x-AnimeSharp for anime, denoise: 0.2, tile_width: 1024, tile_height: 1024, seam_fix_mode: Half-Tile, seam_fix_denoise: 0.2, force_uniform_tiles: True.

For non-anime / photographic styles: 4x_NMKD-Siax_200k or 4x-foolhardy-Remacri instead.

Decision tree

Image looks AI / has issues
│
├─ Face/body skin DIFFERENT colors → Recipe A (FaceDetailer tune + ColorMatchV2)
│
├─ Hand looks broken (fingers wrong) → Recipe B (Hand FaceDetailer pass)
│   └─ Hand still broken after Recipe B → also fix source prompt
│
├─ Skin looks waxy / image feels sterile → Recipe C (sampler swap + grain + CA)
│   └─ Order: sampler first (biggest win), then grain+CA, then prompt tweaks
│
├─ Pipeline has split-stage KSamplerAdvanced → Recipe D (collapse to single KSampler)
│
├─ Upscale chain is `4x ESRGAN → re-encode → KSampler` → Recipe E (UltimateSDUpscale)
│
└─ Multiple issues → fix one at a time, verify with compare_images, then next

Verification protocol (RUN THIS BEFORE DECLARING SUCCESS)

Past sessions have shown that "look at the result and summarize" is NOT enough — the user catches artifacts the agent misses, repeatedly. Before reporting back:

1. run_workflow() — queue the modified workflow.
2. view_file(filename) from output_files. Actually look at the image.
3. Walk the failure-mode checklists below. Don't skip — look specifically for each item, name what you see.
4. For inpaint output specifically, also walk the inpaint failure-mode checklist (next section).
5. Compare directly with compare_images([{filename: before}, {filename: after}]) for A/B verification of changes.
6. State explicitly what could still be wrong. Don't say "this looks great" without naming what you checked. If you see a potential issue (mask seam, asymmetry, color drift), call it out — let the user decide if it matters. Better to flag and be wrong than miss and have the user catch it.

If the fix introduced a new artifact (common — e.g., teal cheek from over-saturated ColorMatch), tune DOWN before adding more nodes.

Inpaint failure-mode checklist

When the workflow ends with an inpaint pass (FaceDetailer, InpaintModelConditioning, etc.), check these specifically:

Symptom	Cause	Fix
Mask seam visible as a hard edge between regenerated and preserved areas	Mask boundary too sharp, no feather	Raise feather / noise_mask_feather on the detailer; or grow + blur mask before inpaint
Phantom limb/finger at mask edge (model invented a hand/foot/sigil)	Mask was too generous OR prompt too vague — model hallucinated to fill an ambiguous shape	Tighten mask. Add explicit negative for the hallucinated thing (e.g., (extra hand, sigil, tattoo:1.2)). Drop denoise.
"Two halves" — anatomical break mid-limb where mask sliced through	Mask cut through the middle of an anatomically continuous region	For limbs: use keypoint polyline masks (see comfyui-mask-strategy skill). For arbitrary shapes: hand-paint or grow mask to include the whole region.
Disconnected joint (wrist not joining forearm, head floating off shoulders)	Mask covered one connected element but not the other (e.g., face but not the hand touching chin)	Expand mask to include both, OR combine two detectors (face_yolov8m + hand_yolov8s → ImpactSEGSConcat → SegsToCombinedMask).
Transplanted feature — face/hand crisp but body softer	Detailer denoise too high (>0.55), creating a render-fidelity seam	Drop denoise to 0.5; reduce cycle from 2 to 1
Color/material mismatch between inpainted and surrounding region	No color match step after inpaint	Add ColorMatchV2 (KJNodes) with pre-inpaint image as reference, method mvgd, strength 0.5
Lost details in adjacent areas (chest armor changed, bracer trim disappeared)	Mask grew too large, included regions you wanted preserved	Shrink mask. Use a more precise mask source (keypoint or paint instead of generous CLIPSeg).
Naked patch in the middle of a clothing inpaint (e.g., bare elbow under a sleeve mask)	CLIPSeg threshold too high; gap in mask	Drop threshold by 0.05-0.1, OR enable fill_holes: true on GrowMaskWithBlur
Inpaint pass unchanged the region	Denoise too low (<0.3)	Raise denoise to 0.5+ for actual rebuild; use 0.3 only for "polish" passes

Iteration discipline

• Each inpaint pass is destructive inside the mask. Iterating with different mask parameters gives N different broken outputs because the mask boundary jitters between runs. The fix is usually to change strategies (e.g., CLIPSeg → keypoint → manual paint), not to re-tune the same one.
• Preview the mask before running the inpaint. Wire mask output → MaskToImage → PreviewImage and check it BEFORE spending compute on a full inpaint pass. Most "bad inpaint" results are actually "bad mask" diagnosed too late.
• When auto-masking fails twice on the same region, recommend manual mask painting. It's not a failure of the agent to ask for human judgment on where to draw a boundary. The user can paint a mask in ComfyUI's MaskEditor in 30 seconds; the agent might burn 5 inpaint runs guessing CLIPSeg parameters.

Escalation paths (when recipes aren't enough)

These are pointers, not full recipes — propose to the user before wiring up:

• ControlNet for pose/anatomy control. Useful when hands are consistently broken across many seeds and detailers can't save them. Common preprocessors: openpose (full body pose), dwpose (hand pose specifically), depth (3D structure). User has comfyui_controlnet_aux installed.
• IPAdapter for character/style consistency across runs. If the user wants the same character in multiple poses.
• InpaintingForEach / Manual mask for specific region rework when YOLO detectors miss the target area.
• Different base model. Some issues are model-level: if Illustrious consistently breaks hands for the user's prompt style, suggest trying NoobAI, Hassaku, or a checkpoint with stronger anatomy training.
• Higher resolution generation (e.g. 1024×1536 base) instead of 832×1216 + heavy upscaling. More tokens, more compute, but anatomy comes out cleaner.

Common pitfalls (learned from real iteration)

• Over-aggressive ColorMatch (strength: 0.7+ with mkl) → teal/blue blotches in face highlights. Drop to mvgd + 0.5.
• High denoise + cycle 2 on hand detailer → "transplanted" hand (different fidelity than body) AND invents accessories (rings, sigils, tattoos). Stay at denoise: 0.5, cycle: 1.
• Heavy prompt weights (:1.2)+ on detailer wildcards → invented decorations the user didn't ask for.
• Setting upscale_by but it doesn't take effect on next run — UI cache race. After set_widget, immediately run_workflow from the no-args form (it pulls fresh state through the bridge); don't pass an old workflow dict.
• Different sampler = different denoising path even at same seed. Switching euler_a → dpmpp_2m_sde will change colors/composition. If you want to A/B compare ONLY the sampler change, lock all other variables and tell the user the composition will shift.

Tools you'll use most

• view_file(filename) — see the output image inline
• compare_images([{filename: a}, {filename: b}]) — side-by-side A/B
• describe_graph() — token-cheap structural overview of current workflow
• get_node_widgets(node_id) — read one node's settings
• set_widget(node_id, name, value) — change one widget
• add_node(class_type, x, y, widget_values) — add a new node (e.g., FaceDetailer, ColorMatchV2)
• connect_many([...]) — wire many connections in one round-trip
• run_workflow() — queue + wait for the open tab's workflow

Final pre-flight checklist before declaring "done"

• Face skin tone matches body skin tone within the scene's color cast
• Both hands have correct finger count (5 visible from current angle, or correctly occluded)
• Eyes have slight asymmetry (real faces aren't perfectly symmetric)
• Skin has visible texture variation, not airbrushed gradient
• Background has atmospheric character (depth, atmosphere, not "render asset")
• No obvious sampler artifacts (banding, halos, oversharpened edges)
• Grain/CA is subtle, only visible on close inspection
• Composition matches the user's intent (color/style hasn't drifted from request)