Model reference · open weights
Chroma1-HD is an open-weight image model from lodestones, listed in the AxForge catalogue. AxForge can bring it up on EU-owned hardware for you on request — with the licence handled where one is required.
About
Chroma1-HD Chroma1-HD is an 8.9B parameter text-to-image foundational model based on FLUX.1-schnell. It is fully Apache 2.0 licensed, ensuring that anyone can use, modify, and build upon it. As a base model, Chroma1 is intentionally designed to be an excellent starting point for finetuning. It provides a strong, neutral foundation for developers, researchers, and artists to create specialized models. for the fast CFG "baked" version please go to Chroma1-Flash. Key Features High-Performance Base: 8.9B parameters, built on the powerful FLUX.1 architecture. Easily Finetunable: Designed as an ideal checkpoint for creating custom, specialized models. Community-Driven & Open-Source: Fully transparent with an Apache 2.0 license, and training history. Flexible by Design: Provides a flexible foundation for a wide range of generative tasks. Special Thanks A massive thank you to our supporters who make this project possible. Anonymous donor whose incredible generosity funded the pretraining run and data collections. Your support has been transformative for open-source AI. Fictional.ai for their fantastic support and for helping push the boundaries of open-source AI. You can try Chroma on their platform: [](https://fictional.ai/?ref=chromahf) How to Use diffusers Library install the requirements pip install transformers diffusers sentencepiece accelerate Quantized inference using gemlite ComfyUI For advanced users and customized workflows, you can use Chroma with ComfyUI. Requirements: A working ComfyUI installation. Chroma checkpoint (latest version). T5 XXL Text Encoder. FLUX VAE. Chroma Workflow JSON. Setup: 1. Place the T5xxl model in your ComfyUI/models/clip folder. 2. Place the FLUX VAE in your ComfyUI/models/vae folder. 3. Place the Chroma checkpoint in your ComfyUI/models/diffusionmodels folder. 4. Load the Chroma workflow file into ComfyUI and run. Model Details Architecture: Based on the 8.9B parameter FLUX.1-schnell model. Training Data: Trained on a 5M sample dataset curated from a 20M pool, including artistic, photographic, and niche styles. Technical Report: A comprehensive technical paper detailing the architectural modifications and training process is forth
Summarised from the published model card. Read the full card on the HuggingFace links below.
Specifications
| Maker | lodestones |
|---|---|
| Type | Image models |
| Parameters (lead) | 8.9B |
| Variants | 1 |
| Runs with | diffusers |
| Released | 2025-08-08 |
| Popularity | 73k downloads / month |
| Likes | 399 |
| Licence | Open weights |
How it works
Variants
Open weights ship in several sizes and precisions. One page, all the variants — pick the one that fits your GPU. VRAM figures are estimates from model size.
| Variant | Params | Precision | VRAM | Fits 16 GB | Weights |
|---|---|---|---|---|---|
| Chroma1-HD | 8.9B | BF16 | ~20.5 GB | ✓ | Weights ↗ |
Using it via the API
Once AxForge deploys chroma1-hd for you, it answers on the OpenAI-compatible API — the same base URL and keys as every other model. (chroma1-hd below is illustrative; you get the exact model name on deployment.)
$ curl -sS https://api.axforge.ai/v1/images/generations \
-H "Authorization: Bearer $AXFORGE_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model":"chroma1-hd","prompt":"a red bicycle","size":"1024x1024"}'
Details
Tags
Licence
Open weights under apache-2.0 — commercial use is permitted. Deploy it on AxForge EU hardware on request. Read the licence ↗