Germany Allied Occupation Zone Stamp With Shimmery Paper

So a while back I purchased a large lot of German stamps and covers from all eras of German postal history on Catawiki.
Now there are these greenish yellowish stamps that clearly have a Peace theme. They seem to be different varieties. I'm most curious about the one in the middle. It's slightly larger than the other two and printed on paper that's shimmery/glittery. I don't own a Michel specialized Germany catalogue yet, and I'm curious about what type of paper it is. Anyone have any ideas? I've included a picture, but you can't really see the shimmery effect on it. Only if you hold the stamp up to the light.

My 2015/16 Michel specialized shows these varieties:
959a black-grey-yellow to blackish olive-yellow
959aa blackish yellow-olive
959b black-grey-yellow to blackish olive-yellow (UV strong fluorescence)
959c blackish olive-yellow (UV yellowish-, spotted)
959d dark brownish-olive
Can't find any specific mention of paper varieties.

Ah it's probably the strong fluorescence then, thanks. Like it was visible in sunlight that strong.

"Shimmery paper" Never heard that term used before. Is that anything like the shine of the glazing as on the frosting on a donut? Both sides or just on the gum side?

A translator like Linguee will return 'shimmery' for the Dutch word that, philatelically, means 'glossy.'

It will pop up for several Dutch words that could also mean 'glimmering,' 'glittering,' or 'shiny.'

I haven't checked the back yet, only the front. I was just going through the stock book cataloguing all of the stamps and when I turned the page I noticed one of the stamps had shimmery details appear in the sunlight while the others didn't.

Fenrik07, I think what you are seeing is normal, just a relatively fresh example. In any case, I've seen this often enough with the mark values of this set.