Need Help Reich Stamp 1919 - Colour

Hello everybody! I am a new member here, but the following question bothers me for about half a year. I have a few stamp catalogue from several periods, the latest from 2005, but in none of them found anything about this variety: a Reich stamp, from 1919, 25 PF, but it's not green as should be, it's blue (the 30 Pf stamp has 3 mentioned colour variety!). The cancellation on the stamp seems to be all right: Floha (I found out, that this town still exists), the date (1919, after 1 July, the first day). On the other hand the stamp has little value, so no reason to falsify it(?).If decoloured (due to water or light), why only the green colour and the red not? (and it is not mentioned in the catalogues, that this stamp is sensible to warm water or light). Please take a look at this picture, and if you have seen or also have a blue 25 Pf. stamp please signal it.
Thanks!
Wadmalatz

'why only the green colour and the red not?'

Well, green is a mixture of blue and yellow, so some processes turn green to blue but they don't affect other colours, such as red. Green inks are notoriously unstable.

That said, your stamp doesn't look to me like it's what we call a 'colour changeling.' It looks more like a colour error, which could make it quite valuable.

I think you need to take it to an expert!

'the stamp has little value, so no reason to falsify it(?).'

Well, many Germans were very, very poor in 1919 and no doubt people were trying to 'clean' the postmarks off stamps so they could re-use them. If your stamp is a colour changeling, then this is probably how it happened.

The pmk looks a little "washed"
Some scallywag has been playing with a chemical?


Mr Balboa was feeling a little blue on this one.

Great Britain SG213 1900 queen vic halfpenny blue/green
When existing in bright blue is a "colour changeling"
see your catalogue.

Thanks. Indeed!! Good point. Now the postmark (and the green colour)gives me too a headache, and makes me more suspicious. That's why I like to ask, before spending eventually money on expertize. But who knows, maybe there is somebody else who has another blue 25 pf.
No SG, only Mi and Y&T from the 70`-`80's plus few Spec. (Germany,Austria, Hungary, Nederland).
Thanks.