Hey Hi Hello!
Wow. Sheesh. Got Dam. This has been one hell of a journey. I've been pursuing a reliable and high quality upscale workflow since I started playing with stable diffusion in automatic1111 since about 15 months ago. I have had all sorts of ups and downs, successes and failures. At first there werent really any issues but as I tried to push outputs bigger and bigger (while many were looking for added detail and not massive images) the problem I had was with tiling. No matter what I tried, I would end up with some degree of tiling. This was seen as normal and I was often told to just fix it in post processing... which I did do off and on at times but it really wasnt the ideal scenario. Simply put, I wanted a perfect upscale from small to very large. I was fine with minor sharpening and no real increase in minute details but that damn tiling just wouldnt take the L.
I have been pushing this 8gb graphics card as hard as I can manage. There was a point where I was rendering out 9k x 12k images, but again... T I L I N G. The tiles would rear their ugly heads and it was especially noticable in areas of solid color or fine gradients. I realized eventually that it looked like a checkerboard with alternating light and dark squares.
I started this quest around sept 2022 as i finally gave in and stopped using discodiffusion notebooks on colab and installed automatic1111 locally. Fast foward to 2024 and here I am. Still researching, digging, excavating, fighting, for a good quality upscale.
And for all of my effort and frustration, I do believe I am finally on the right track. Im as close as Ive been to a perfect upscale ( i think ). This method is more VRAM Intensive than using tiled upscaling with something like sdultimate, and because of that I can only test it up to 4096x4096. If you have more than 8gb of VRAM im sure you'll be able to push it way past that. And of course you could mix and match it with hi-resfix or sdultimate to see if you can maintain or improve fidelity as you go up in size. Anyhow...
Attached is the workflow im currently playing with.
There are 3 Note Nodes on the left. Theyre exactly the same with just different colors. Delete the colors you dont like or change them. Whatever. The note nodes explain the path of data through the workflow.
Workflow TLDR: Image generation > Iterative Latent Upscaling > Contrast and Saturation Adjustments > Iterative Image Upscaling > Contrast and Saturation Adjustments > Iterative Image Upscaling > Contrast and Saturation Adjustments.
The notes explain the path of the data through the color coded groups. You should be able to figure it out from there, its not really that complicated. Make sure youre picking the appropriate models, upscaling models, samplers, and schedulers. AND VAE. If youre getting washed out faded image results at any point, youll need to select the appropriate VAE in the relevant VAE Loader then CONNECT THEM to the VAE INPUT CONNECTORS in the relevant Color Coded Group!!!! Because not all models have a vae baked in! DUH!!!
The cover image is 2048x2048. I'll try to remember to upload the 4k x 4k when it finishes.