Originally, the Color Bleed effect was noticed in photography. As you take a photo of something colorful, with high brightness, the color in photo may get a bit washed - closer to white. This effect wasn't too unwanted, and sometimes even simulated in 3D rendering software to make images more photo-realistic. I added the effect to each of the Shaders of my Playtime Painter Asset (optional, can be toggled ON/OFF globally). Basically it's just a simple operation of:
float3 mix = col.gbr + col.brg; col.rgb += mix * mix*bleedStrength;
Color from each channel (Red, Green, Blue) "leaks" or "bleeds" into other channels. This would happen in certain older camera types.
You can compare the effect in the images above. First - with color bleed; second - without. Overhead of Red color fills Blue and Green channels, adding towards white. Brightness in both cases is incredibly high (and same). Increasing brightness even further will not change the second image by much, it will only make the edge between red and black more sharp. The first image, on the other hand, will keep loosing red in favor of white as the brightness increases.
The effect can be more subtle in normal light:
Since I use color to power of 2, Bleed is more noticeable when brightness is above 1. Also, you will see more of it with high-contrast colors, other colors will just become brighter.
As I was going to publish the article, I noticed that with Color Bleed, the sky, which I would usually set to be more lite blue manually, actually looks the way it is supposed to look.
In conclusion: I'm not saying that Color Bleed should become a standard for Shaders, but it is certainly something to be mindful of when finding ways to achieve the desired look.
Update [Same day but middle of the night]
I did a bit more trying things out with Color Bleed. I feel like with Color Bleed I am more comfortable with this high-contrast colorful textures. Without CB bright color would become more acidic, with it - all gets nicely whitened. And, in the shadow, in the darker areas, color is not affected. So less bright areas feel almost relaxing because everything is more colorful. The brighter scenes feel bright and maybe washed in some way, but it's better then making them this unreal acidic color. So, I guess Color Bleed is cool.