FLUX 3 Klein workflow by me Two-pass HD pipeline for FLUX 3 Image Klein, the best of my workflows for textin images (signs, posters, album covers...).━━━━━━━━━━━━━━━━━━━━━━━━━━━━WHAT'S INSIDE━━━━━━━━━━━━━━━━━━━━━━━━━━━━- FLUX 3 Klein int8 with the official timestep shift (alpha 16)- Optional BFL Prompt Upsampler: turns a short prompt into a detailed one- Optional layout bounding boxes- Two-pass HD + optional Ultimate SD Upscale 2x- Resolution picker: just choose a ratio + megapixels- Same clean design as my other workflows: numbered groups, group toggles, readable node titlesBuilt and tested on an RTX 4070 Laptop 8GB / 16GB RAM.Flow: prompt -&gt; (prompt upsampler) -&gt; pass 1 -&gt; latent 1.5x -&gt; pass 2 HD -&gt; color match -&gt; save HD -&gt; USD 2x (group ②) -&gt; color match -&gt; save USDToggle each group on/off with the bars above the groups.Settings:- Timestep shift: ModelSamplingFlux 2.77 (alpha 16, official value)- Pass 1: euler / simple, 16 steps, CFG 1- Pass 2: latent upscale 1.5x (bislerp), 16 steps, denoise 0.45- Color match (mkl 0.5) keeps the colors of pass 1- USD: 2x with 4x Remacri, 4 steps, denoise 0.15, color match mkl 0.7- Default size: 3:4 portrait, 1.0 MP. 2 MP also looks great (change it in "Resolution")- Negative prompt has no effect (CFG 1)Prompt Upsampler:Uses Qwen3.5 9B to rewrite your prompt. It's slow with 16 GB of RAM: switch itoff in the node if you write detailed prompts yourself.Models (accept the license on Hugging Face first):<a target="_blank" rel="ugc" href="https://huggingface.co/black-forest-labs/flux-3-image-klein-comfy">https://huggingface.co/black-forest-labs/flux-3-image-klein-comfy</a>- flux3-image-klein-int8-convrot.safetensors (diffusion model)- qwen3vl_4b_int8_convrot.safetensors (text encoder, type flux3)- qwen3.5_9b_flux3_prompt_upsampler_w4a8.safetensors (prompt upsampler, optional)- flux2-vae.safetensors (VAE)- 4x_foolhardy_Remacri.pth (upscaler)Custom nodes:- rgthree-comfy: <a target="_blank" rel="ugc" href="https://github.com/rgthree/rgthree-comfy">https://github.com/rgthree/rgthree-comfy</a>- KJNodes: <a target="_blank" rel="ugc" href="https://github.com/kijai/ComfyUI-KJNodes">https://github.com/kijai/ComfyUI-KJNodes</a>- ComfyUI_UltimateSDUpscale: <a target="_blank" rel="ugc" href="https://github.com/ssitu/ComfyUI_UltimateSDUpscale">https://github.com/ssitu/ComfyUI_UltimateSDUpscale</a>Needs a recent ComfyUI (FLUX 3 support).

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