Jokes aside, I suppose it's novel in the sense that it can be achieved with artificial _blue_ light.
My understanding was that it was various forms of UV from the sun that caused "bleaching", whereas the paper points out that it is not UV in this case, and in fact, the UV can cause additional staining.
Maybe I should have emphasised the word "artificial" rather than the word "blue", the implication was that it's not the only type of blue light, the sun being the obvious one.
The thing about the sun is, you get no light when there's no sun, and some countries don't even get daylight for several months of the year!
It's an interesting idea, and how it would work with colours other than "bleached" would be the interesting part.
Presumably it wouldn't work on black without fading the garment, but given how we've seen things fade in shop windows, I wonder if there's some novel applications for removing other types of intentional "stains" like ink, or paint, and particularly if they're under/behind a surface like a clear-coat or glass or something else that prevents physical access.
That would be an interesting one, I have a strangely related story that not too long ago my toddler drew _all over_ a yellow suede sofa with a blue ballpoint pen, was a nightmare to get it out without making the pristine sofa look like a drowned rat.
I am a common "poo-pooer" of bad submissions on here, and comments not in good faith
But this paper taught me something I had no idea about as a 33 year old.
Also in the comment chain someone mentioned/brought up using peroxide/sunlight to clear up old yellowed plastics which is....monumental to some of my projects :)
Ultraviolet light is ionizing. Things oxidize and often whiten in sun because the UV light (the part of the UV spectrum as you go below ~315nm) ionizes and causes chemical reactions, in most cases by splitting O2 which is then charged O atoms that want to react with things.
445nm light isn't ionizing at any brightness, and shouldn't be catalyzing oxidation. Didn't look at it in detail but what is their claim on mechanism?
