A family of early-fusion base models ranging from 0.1B to 4B parameters can outperform late-fusion text-to-image baselines without using frozen language models or text-only pretraining. Developed by Radical Numerics as Halcyon, these models were trained from scratch on 100M image-test pairs from GPIC. The 1.6B Halcyon model beats the JiT-T2I-XXL/8++ baseline while using 275x less pretraining compute, and the 0.52B version outperforms LlamaGen-XL/8 with 18.2x less compute, including the cost of the language models used by the baselines. Radical Numerics has made the models and their training recipes open.