@Artisan-West Now hang on, I said I wasn’t finished yet. I humbly apologize for making the boneheaded mistake of hitting Return instead of Shift-Return, but I’m hoping this post will make up for it. And for that deleted post above, which was another mistake. And for replying to myself. The list goes on and on…
I do have to stop for a moment and say that I try very hard not to troll anyone, over anything at all, no matter how trivial, because I believe you should speak in good faith or just not speak at all. I wouldn’t do it to someone face to face, and doing it to someone on the internet doesn’t magically make it OK. You had no way of knowing any of that, so I can’t hold it against you for expecting the worst. But now you know. 
So back on topic. My argument here is that the real difference can be seen in the honey jar label, comparing the effects of Color NR to having Color NR turned off. (I found that comparing it with the noisy original didn’t bring the issues out as clearly, because there are too many uncontrolled variables. And, well, too much noise.)
Here’s my comparison. I used AI Clear because I find it more effective overall for this particular image, but the effects of the Color NR slider look pretty much the same to me with either AI model. I can make the same comparison using Denoise AI if you think it adds to the discussion.
Clear AI (Auto) with no color NR:
And AI Clear (Auto) with color NR 0.26:
It’s most obvious around “Honeyville.” This really cries out for an animated GIF, but if you can open them in an image viewer that lets you flip back and forth, the difference will jump out at you immediately.
I’ve enlarged it (probably way too much) to make it easier to see, but you don’t have to be a pixel peeper — although I’ll confess that I am — to see that the red gets darker in general because the black outlines are bleeding into it. And I suspect the desaturation is just a consequence of the bleeding.
For the sake of fairness, I’ll point out that the color NR does remove a lot of noise in the purple parts of the label that AI Clear did not.
Which comes back to what I said originally: traditional color noise reduction has always been a trade-off between noise and overall color accuracy for me. I’ve had to make that choice in Photoshop, Lightroom, Noiseware (that’s going back a few years), Noiseless, and here as well. I generally leave it turned off. And with this image, I think AI Clear on its own does an amazing job of it without smearing the details. I didn’t expect it to work that well on massive amounts of chroma noise.
So my point is this: it’s the Color Noise Reduction slider that causes colors to bleed, not the AI algorithms. I think it’s the same kind of chroma noise filtering you get in other software, mainly for the benefit of people who are already used to it and like the look. And I’m not saying that’s a bad thing. I’ve used it myself for effect, but I’d argue that the AI models have a much more natural look to them.
