I'm sorry, but you can't tell from the pictures what type of film they have used. It should be the other way round. If you clearly know the type of film, then you can try to find out the colours. In addition, you need to know what colours were available, or should I say allowed according to the paint regulation.
Red around Norway was true for another operation. For Rheinübung it was clearly yellow, as stated by an official document (which made its way round the internet some time ago). The dark grey you see at Grimstadt is indeed dark grey. It replaced the yellow which is *visible* during the stay at Gotenhafen.
The aerial view you named *Hamburg?* ~ Believe me, since years I've been pondering about the different *colours* in that photo. I have a theory, but I don't have proof so I keep my lips sealed.
Anyway, if you have a colour photo of Bismarck showing the red, then I owe you an apology (in return for showing me that photo ...

).
@ Anatoly ~ Too bad, my 1980 edition of the Baron book doesn't contain this photo plus the caption. I don't know what to say regarding the latter, but all I've heard is that the black appearance of the barrels plus the light coloured (metal?) rings had something to do with the shooting trials (AVKS-Schießen) in the Baltic. It is the first time I heard something about red lead used on barrels and I don't see a benefit here. Well, I'm no expert by any means, but could it be that there went something wrong during the translation from German to Russian to English?
Happy guessing ~ Olaf!