Ideogram 4 Local Execution in ComfyUI

Multiple paths exist to generate with Ideogram 4. The simplest is the cloud API node (IdeogramV4), but it requires a comfy.org API key. For local execution without cloud dependency, use the native Ideogram4Scheduler + model files.

Path A: Cloud API Node (Simplest, but requires key)

Node: IdeogramV4
Location: comfy_api_nodes/nodes_ideogram.py
Requires: COMFY_CLOUD_API_KEY env var or login

Error without auth:

Unauthorized: Please login first to use this node.

Works with structured JSON prompt (scene + style + background blocks). The easiest if you have the key.

Path B: Local Native Pipeline (No API key, but 28 GB disk needed)

Recommended when: No comfy.org auth available or prefer full local execution.

Required Model Files

File	Size	Folder	Source
`ideogram4_fp8_scaled.safetensors`	~8.6 GB	`models/diffusion_models/`	HuggingFace: `Comfy-Org/Ideogram-4`
`ideogram4_unconditional_fp8_scaled.safetensors`	~8.6 GB	`models/diffusion_models/`	HuggingFace: `Comfy-Org/Ideogram-4`
`flux2-vae.safetensors`	~320 MB	`models/vae/`	HuggingFace: `Comfy-Org/flux2-dev`
`qwen3vl_8b_fp8_scaled.safetensors`	~9.9 GB	`models/text_encoders/`	HuggingFace: `Comfy-Org/Qwen3-VL`
`gemma4_e4b_it_fp8_scaled.safetensors`	~5.4 GB (optional alt)	`models/text_encoders/`	HuggingFace: `Comfy-Org/gemma-4`

Total: ~28 GB

Model Verification Recipe

A file can have the correct size on disk but still fail to load with SafetensorError: incomplete metadata. This happens when a download is interrupted and resumed incorrectly, or when the file was copied incompletely.

Use this Python script to verify any .safetensors file before trusting it:

import struct, json, os

def verify_safetensors(path):
    """Check header metadata against actual file size."""
    actual = os.path.getsize(path)
    f = open(path, 'rb')
    header_len = struct.unpack("<Q", f.read(8))[0]
    meta = json.loads(f.read(header_len))
    total = 8 + header_len
    for k, v in meta.items():
        if isinstance(v, dict) and "data_offsets" in v:
            total += v["data_offsets"][1] - v["data_offsets"][0]
    return {
        "actual_bytes": actual,
        "expected_bytes": total,
        "ok": total == actual,
        "header_keys": len(meta),
        "missing": total - actual if total > actual else 0,
    }

# Example
result = verify_safetensors("models/text_encoders/qwen3vl_8b_fp8_scaled.safetensors")
print(result)
# If ok=False, the file is corrupt and MUST be re-downloaded.

Command line shortcut (in Container):

python3 -c "
import struct, json, os; p='/opt/ComfyUI/models/text_encoders/qwen3vl_8b_fp8_scaled.safetensors'
f=open(p,'rb'); h=struct.unpack('<Q',f.read(8))[0]; m=json.loads(f.read(h))
t=8+h; [t:=t+v['data_offsets'][1]-v['data_offsets'][0] for k,v in m.items()
 if isinstance(v,dict) and 'data_offsets' in v]
print('ok=',t==os.path.getsize(p))
"

Text Encoder Compatibility Note

Ideogram 4 supports two text encoders:

qwen3vl_8b_fp8_scaled.safetensors (Qwen3-VL, ~9.9 GB) — primary, higher quality
gemma4_e4b_it_fp8_scaled.safetensors (Gemma 4, ~5.4 GB) — lighter alternative

If one fails (e.g., corrupt download), try the other.

ComfyUI BluePrint Workflow (API Format)

The canonical workflow is shipped as a BluePrint JSON in ComfyUI:

blueprints/Text to Image (Ideogram v4).json

This uses the Ideogram4Scheduler + DualModelGuider with the two UNet files (conditional + unconditional) for asymmetric classifier-free guidance.

Key nodes in the BluePrint:

Ideogram4Scheduler → outputs SIGMAS (replaces BasicScheduler)
DualModelGuider → combines positive + unconditional models
CFGOverride → cfg schedule override (start/end percent)
EmptyFlux2LatentImage → 128-channel latent
SamplerCustomAdvanced → with euler + Ideogram4Scheduler sigmas

Common Errors — Local Path

1. SafetensorError: incomplete metadata, file not fully covered

Cause: File is structurally corrupt (wrong tensor offsets in header).
Fix: Run verification recipe above. If ok=False, delete and re-download from HuggingFace.
Important: ls -lh showing the right size is NOT sufficient. The header values must match the data offsets.

2. Unauthorized: Please login first to use this node

Cause: Using IdeogramV1/V2/V3/V4 API node without comfy.org auth.
Fix: Switch to local pipeline (Ideogram4Scheduler + model files), or add COMFY_CLOUD_API_KEY.

3. expected input[1, 128, 32, 32] to have 16 channels

Cause: Using FLUX.1 VAE (ae.safetensors) instead of flux2-vae.safetensors.
Fix: VAE must be flux2-vae.safetensors (or taef2).

References

ComfyUI BluePrints: blueprints/Text to Image (Ideogram v4).json
Model source: https://huggingface.co/Comfy-Org/Ideogram-4
Text encoder: https://huggingface.co/Comfy-Org/Qwen3-VL
Alternative encoder: https://huggingface.co/Comfy-Org/gemma-4

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