@ -131,7 +131,82 @@ But fear not, there are a few techniques to increase image size from 512px to so
* Pixel space upscale with model: There are special models designed for a better upscale result. Some even extrapolate details.
* Pixel space upscale with model: There are special models designed for a better upscale result. Some even extrapolate details.
* High Resolution Fixing: Uusually abbreviated to HR-Fix or even furthetr to HRF, this method is a combination of many of the above. It uses many steps, takes longer, but results in high-detail images. There's the added bonuse that stable diffusion can even "fix" broken parts of the image! Sometimes.
* High Resolution Fixing: Uusually abbreviated to HR-Fix or even furthetr to HRF, this method is a combination of many of the above. It uses many steps, takes longer, but results in high-detail images. There's the added bonuse that stable diffusion can even "fix" broken parts of the image! Sometimes.
What is this latent space vs pixel space thing?
* Latent space is the zone of chaos and randomness stable diffusion works in. These aren't really images like human eyes see, but math-magic representations the computer works with.
* pixel space is an actual image, rendered in pixels. The things human eyes and graphic arts programs like to work with.
* VAE Decoding and Encoding is used to translate a latent image to pixel and back.
* Some proccesses can only be done in latent space (like KSampling) and others only in pixel space (color correction, model upscaling)
There are some caveats to HR-fixing.
* work in as many small steps as you can stand.
* stick to multiples of 64px. This can be challenging with images of different aspect ratios. There are some custom nodes that help with this.
* if the aspect ratio makes multiples of 64px challenging, do the image upscales in pixel space
* due to the math involved, even then it is best to do multiples of 8 pixels.
* it is better (and faster) to go through many low-resolution latent space samples and _then_ do a large pixel upscale. This gives lots of detail for the pixel upscale to work with.
But first, let's make a basic HR-Fix.
* at the right side of the workflow, move the VAE Decode and Save Image nodes to the right (try and grab the VAE reroute on the bottom too).
* about as far as the distance they currently occupy, maybe a touch more.
* put a _Upscale Latent_ node next to the Ksampler
* connect the LATENT output on the Ksampler to the Samples input on the _Upscale Latent_ node.
* put a _KSampler_ node between the Upscale Latent and the VAE Decode.
* connect he LATENT output from the _Upscale Latent_ node to the latent_image input on the new _KSampler_ node.
* connect the LATEN output on the ksampler to the samples input on the _VAE Decode_ node.
* this will also erase the noodle from the old ksampler to the vae decode
* On the Upscale Latent node, increase wideth and hight by 64pixels. This is easy by clicking the arrows on the right, next to the numbers.
But wait! We're not done. The new KSampler still has a bunch of inputs that are empty. That's because the sampler needs to know what to do with the latent image.
See the model rerout hanging out at the corner of the positive prompt?
* lect click to activate it.
* Ctrl-C to clone it.
* move mouse a little to the right (above the older ksmampler is fine)
<imgsrc="cloning reroutes 1.png"align=middle>
* ctrl-V to paste the cloned reroute
<imgsrc="cloning reroutes 2.png"align=middle>
* now connect them
<imgsrc="cloning reroutes 3.png"align=middle>
* then drag it right so it is close to the new KSampler
<imgsrc="cloning reroutes 4.png"align=middle>
* and connect it to the model input on the new KSampler
<imgsrc="cloning reroutes 5.png"align=middle>
* The reroute is still in the clipboard, so do another ctrl-v below that initial mode reroute.
<imgsrc="cloning reroutes 6.png"align=middle>
* This time, connect the CONDITIONING output from the Positive prompt to the new reroute. The name will change, but not the color.
<imgsrc="cloning reroutes 7.png"align=middle>
* Right Click on the reroute node, left click on Colors, then select Yellow
<imgsrc="cloning reroutes 8.png"align=middle>
* repeat the last few steps to make a second reroute for the negative node and change color to black.
<imgsrc="cloning reroutes 9.png"align=middle>
* now tidy them up a bit.
* hint, shift-lelft mouse when dragging "snaps" the node to the grid. Makes them easier to place evenly.
<imgsrc="cloning reroutes 10.png"align=middle>
* Shift-Left Click on both the new conditioning nodes to select both of them.
<imgsrc="cloning reroutes 11.png"align=middle>
* Contrl-C to clone them to clip board
* Ctrl V a little to the right to paste them on the workflow.
<imgsrc="cloning reroutes 12.png"align=middle>
* Run nuddles from the previous conditioning nodes to the new ones.
<imgsrc="cloning reroutes 13.png"align=middle>
* and drag them to the right. They should still be selected, so shift+left mouse will move both of them.
<imgsrc="cloning reroutes 14.png"align=middle>
* then connect them to the inputs for positive and negative.
<imgsrc="cloning reroutes 15.png"align=middle>
* The upscale and ksampler should be ready. If you changed the _Empty Latent Image_ node to test out larger sizes, change it back to 512px.
* Click on Queue Prmpt
* Marvel at the slightly larger and more detailed pixel bottle!
But wait! Isn't this bottle someone different from before? It sure is! And here is why:
* On the new KSampler, denoise is set to 1.000
* This telling the ksampler to treat the laten image input as if it were a new canvas and to extrapolate the result like a new image.
* adjust the denoise down to more closely match the original latent while still adding detail.
* 0.500 is _generally_ a good number for the first "HR Fix"
* click Queue Prompt again.
* Instead of running the whole workflow, comfyui should start at the second KSampler. This is because the there were no changes earlier in the workflow.
wyrde
2 years ago
