FLUX.1

Flux (also known as FLUX.1) is a text-to-image model developed by Black Forest Labs, based in Freiburg im Breisgau, Germany. Black Forest Labs was founded by former employees of Stability AI. As with other text-to-image models, Flux generates images from natural language descriptions, called '' prompts''.

History

Black Forest Labs was founded in 2024 by Robin Rombach, Andreas Blattmann, and Patrick Esser, former employees of Stability AI. All three founders had previously researched the artificial intelligence image generation at Ludwig Maximilian University of Munich as research assistants under Björn Ommer. They published their research results on image generation in 2022, which resulted in creation of Stable Diffusion. Investors in Black Forest Labs included venture capital firm Andreessen Horowitz, Brendan Iribe, Michael Ovitz, Garry Tan, and Vladlen Koltun. The company received an initial investment of million.

In August 2024, Flux was integrated into the Grok chatbot developed by xAI and made available as part of premium feature on X (formerly Twitter). Grok later switched to its own text-to-image model Aurora in December 2024.

On 18 November 2024, Mistral AI announced that its ''Le Chat'' chatbot had integrated Flux Pro as its image generation model.

On 21 November 2024, Black Forest Labs announced the release of Flux.1 Tools, a suite of editing tools designed to be used on top of existing Flux models. The tools consisting of Flux.1 Fill for inpainting and outpainting, Flux.1 Depth for control based on extracted depth map of input images and prompts, Flux.1 Canny for control based on extracted canny edges of input images and prompts, and Flux.1 Redux for mixing existing input images and prompts. Each tools are available in both ''Pro'' and ''Dev'' variants.

In January 2025, Black Forest Labs announced a partnership with Nvidia for inclusion of Flux models as foundation models for Nvidia's Blackwell microarchitecture. The company also announced the release of , designed for customisation and fine-tuning of Flux-generated images and a partnership with German media company Hubert Burda Media for usage of Flux Pro as part of content creation.

On 29 May 2025, Black Forest Labs announced Flux.1 Kontext, a suite of models that enable in-context image generation and editing, allowing users to prompt with both text and images. Alongside this, they launched the BFL Playground, an interface for testing Flux models.

Models

Flux is a series of text-to-image models. The models are based on rectified flow transformer blocks scaled to 12billion parameters. Flux.1 models were released under different licences with ''Schnell'' (meaning Fast or Quick in German language) released as open-source software under Apache License, ''Dev'' released as source-available software under a non-commercial licence, and ''Pro'' released as proprietary software and only available as API that can be licensed by third-party users. Users retained the ownership of resulting output regardless of models used.

The models can be used either online or locally by using generative AI user interfaces such as ComfyUI and Stable Diffusion WebUI Forge (a fork of Automatic1111 WebUI).

An improved flagship model, Flux 1.1 Pro was released on 2 October 2024. Two additional modes were added on 6 November, Ultra which can generate image at four times higher resolution and up to 4 megapixel without affecting generation speed and Raw which can generate hyper-realistic image in the style of candid photography.

Flux.1 Kontext is a series with in-context image generation and editing capabilities. It is available in ''Pro'' and ''Max'' variants with ''Dev'' variant in private beta. ''Pro'' is the highest quality model and can be used to iteratively modify an existing image by using prompt while ''Max'' is optimised for speed of generation. ''Dev'' will be an open-weight model.

Related to Flux is text-to-video model SOTA, under development .

Reception

According to a test performed by ''Ars Technica,'' the outputs generated by Flux.1 Dev and Flux.1 Pro are comparable with DALL-E 3 in terms of prompt fidelity, with the photorealism closely matched Midjourney 6 and generated human hands with more consistency over previous models such as Stable Diffusion XL.

Flux has been criticised for its very realistic generated images. According to media reports, depictions ranged from an image of Donald Trump posing with guns to disturbing scenes, which triggered discussions about ethical implications of technologies developed by Black Forest Labs.

After the release of the model, social media platform X was flooded with Flux-generated images. Black Forest Labs has not provided exact details of the data used to train the model. ''Ars Technica'' suspected that Flux is based on a large, unauthorised collection of images scraped from the internet, a controversial practice with potential legal consequences.

According to a test performed by Japanese technology news website ''Gigazine'' for Flux.1 Kontext, the model series has a good understanding in English language and can easily transfer style of image from photorealistic into anime-style according to prompts given by the user, however its capability to understand Japanese language is quite poor.

Availability

In addition to the official BFL Playground on their website, the Flux models are also widely available through various third-party platforms for creative and professional use. These include repositories on platforms like Hugging Face and Replicate.

References

External links

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Flux models on Hugging Face

Flux models on Replicate

Flux models on FAL.ai

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Unsupervised learning
Text-to-image generation
Deep learning software applications
Artificial intelligence art
Open-source artificial intelligence
2024 establishments in Germany
Software using the Apache license