I don't get it. Do certain parts of the new bills absorb way more infrared?
So it would seem. Presumably on purpose.
Truly it would be far more surprising if it were nonintentional.
That the stripes are white implies that it reflects way more IR, rather than absorb.
We played around today with a new $50 and an active IR scope. It looks to me like the areas in question are covered in a highly IR reflective dye, you can still see the artwork beneath them faintly. However, the $50 looks to have solid bars, without the smaller stripes you see in the above picture.
Sorry if this is already apparent from the page linked, it's broken in my firefox and I can't see the individual bill images.
I wonder if this is the mechanism that dollar-bill readers in soda machines and whatnot use to identify the bills, rather than actually trying to match the images on the bills? And if so, could this lead to a lot of free soda?
I think that the IR is relatively new, at least in comparison to most vending machines. So even if this is the case, you'd have to find very modern soda machines.
Remind me to tell you about the bad $10 bill from Sun. Night. Just a teaser... Andrew Jackson.