"For the two consoles with the more extreme yellowing, White 2L and Burgundy, the yellowing appears to be irreversible"
the before and after pictures for those 2 look pretty good tho, no?
For the photos, it is tough to convey what I'm seeing and what the camera is seeing. The more objective data points using a color picker on GIMP have both the White 2L and Burgundy at a CIE DE2000 of or around 20 for the top screen. For that Y axis, the closer to zero, the more similar the screens are to my control console, and a score of around 20 is noticeable to my eyes as yellowed.
I notice your first datapoint is on day 11, and pretty much everything that can be done has been done for almost all the screens at that point.
It would be interesting to see this tracked a bit more closely in the first week, to know at what point the majority of the work is done, and when you hit the point of diminishing returns.
Indeed that would be interesting. It would take a much better testing rig than I had to have it sample every day or hour without human interference.
I would think that it would also be a bit hard to determine what to do with the information. If you had a lot of consoles, with differing levels of "yellowness" that you could closely test, you could, in theory, nail down a minimum number of days required to "de-yellow". I'm not exactly sure how that information would be useful as this process is, more or less, a last resort before getting a new console or replacing the screen.
After some more time testing this, I've noticed a few things worth mentioning:
While the screens are whiter, on lower brightness levels you can still see "shadows" where the yellowed areas used to be on the screen. This matters more if there was a pattern and not just an even vignette of the yellowing. Looks kind of like that stage light defect on most macbooks.
Oh, I never thought that could happen. That is something I never would have considered. So in some ways, whatever damage is on the LCD, it cannot fully recover.
A friend had an extremely yellowed top and bottom screen DS Lite.
Testing for 2 weeks with full brightness and black screens on it resulted in almost no noticeable change.
Further testing for 2 weeks with full brightness and white screens resulted in some improvement, but the screen tone is still noticeably very yellow compared to my 2 DS Lites.
Interesting that you saw no change. I have to imagine they are the same tech, but I won't pretend to know anything about DS Lite screens. But, yeah, the heavily yellowed screens appear to be beyond repair for the test I performed.