QR Code Monster for SDXL

Time to try another ControlNet for Stable Diffusion XL - QR Code Monster v1 in ComfyUI. This ControlNet can influence SDXL such that the generated image “hides” a scan-able QR code, which at first glance, looks like a photo!

Installing

I am using vanilla ComfyUI, with SDXL and LCM LoRA for SDXL.

All that is needed is to download QR monster diffusion_pytorch_model.safetensors, rename it e.g. to control_v1p_sdxl_qrcode_monster.safetensors, and save it to comfyui/controlnet.

Workflow

Here is the workflow with full SDXL:

Start off with the usual SDXL workflow - CheckpointLoaderSimple > CLIPTextEncodeSDXL prompt and CLIPTextEncode negative prompt
Use ControlNetLoader to load the QR Monster ControlNet
And use LoadImage to load a PNG QR code, sized 1024x1024 - I created my QR codes using the iPhone’s Shortcuts app with the highest Error Correction level selected.
And insert a ControlNetApplyAdvanced node to take the conditioning outputs from both CLIP Text Encoders and pass the conditioning output to a KSamplerAdvanced node
The trick is adjusting the Apply Control Net strength (0.8 to 0.9) and perhaps the KSampler cfg value so that you have a creative image that makes the QR code less obvious but that can still be read - the higher the closer to the original source image.

And here is another with the SDXL LCM LoRA - I go from 20 steps to just 7!

I tested these QR codes on my iPhone - for some images, the Camera app simply could not locate the QR code, but the dedicated (QR) Code scanner could! Add it to the Control Center from the Settings.