This is an Extension for the Automatic1111 Webui, which performs Color Grading during the generation, producing a more neutral and balanced, but also vibrant and contrasty color.
This is the fruition of the joint research between TimothyAlexisVass with their findings, and me with my experience in developing Vectorscope CC
Note: This Extension is disabled during ADetailer phase to prevent inconsistent colors
This Extension comes with two main features, Recenter and Normalization:
TimothyAlexisVass discovered that, the value of the latent noise Tensor often starts off-centered, and the mean of each channel tends to drift away from 0.
Therefore, I tried to write an Extension to guide the mean back to 0. For SDXL, pushing the mean of each channel to 0 yields decent results.
But for SD 1.5, I found out that for some Checkpoints this often produces a green tint, suggesting that the "center" of each channel might not necessarily be at 0.
After experimenting with hundreds of images, I located a set of values for a rather neutral and balanced tone.
When you enable the feature, the output images will not have a biased color tint, and all colors will distribute more evenly; Additionally, the brightness will be adjusted so that bright areas are not overblown and dark areas are not clipped, producing a similar effect like the HDR photos taken by smartphones.
Off | On
Off | On
By encoding images into latent noise with VAE, TimothyAlexisVass discovered that the values for VAE to decode are usually within a certain range, and thus theorized that if the final latent noise has a smaller value range, then some precision is essentailly wasted. This gave me an idea to write a function that can make the latent noise utilize the full color depth, making the final output more vibrant and contrasty.
When you enable the feature, the latent noise will attempt to span across the value ranges if possible, before getting decoded by the VAE. As a result, bright areas will get brighter and dark areas will get darker; Additional details may also be introduced in these areas.
This feature is currently disabled during Hires. fix pass
You can also enable both features at the same time, thus creating some really stunning results!
Since the *internal structure (channel) and the color range of SDXL is different from those of SD 1.5,
this Extension cannot simply work for both of them using the same values. Nevertheless, you can now toggle the version to SDXL and try out the effects:
Off | On
In the Diffusion CG section of the Settings tab, you can make either feature default to Enabled,
as well as setting the Stable Diffusion Version to start with.
- Parameter Settings
- Better SDXL Support
- Generation InfoText
- Better Algorithms
Currently, for extreme cases (eg. a bowl of oranges), the overall colors will be overcompensating
The Tensor of the latent noise has a dimention of [batch, 4, height / 8, width / 8].
- For SD 1.5: From my trial and error when developing Vectorscope CC, each of the 4 channels essentially represents the
-K,-M,C,Ycolor for the CMYK color model. - For SDXL: According to TimothyAlexisVass's Blogpost, the first 3 channels are similar to YCbCr color model, while the 4th channel is the pattern/structure.