This used to be a common style in European ink bottles. One assumes it’s expensive to make.
This company might be thought of as the inventor of the notion of “boutique ink”, since they were also one of the first companies to consciously abandon any notion of competing with ball-points and to focus on the prestige market. My slight inclination to bolshevism makes me want to deride them for this, but they are by all reports rather good inks, if expensive ones. The bottles are also quite good, and worth hanging onto.
Examples (note– I’ve not calibrated my scanner, so these are mere approximations of the true colour):
This is actually showing a little pale
Racing Green: In any non-English-speaking country, this ink is called “English Green”, which makes the box somewhat whimsical for a polyglot. Inspired, one must assume, by the international racing colour of Great Britain, this is an extremely dark green, shading in some pens almost to black, in a way that most people wish a blue-black ink would work. This colour has been discontinued and one might expect any residual stocks to be snapped up at a premium. Close alternatives include Diamine Evergreen and Noodler’s Sequoia Green.
Royal Blue: This is a semi-vintage sample; the bottle I got is labelled as made in “W. Germany”, so it’s at least twenty years old, but probably not much more than that. It’s slightly darker than the current Pelikan version of the colour, but only just. Update: A prolonged use of this ink in a TWSBI Vac 700 saw all the silicone grease dissolved from barrel and rubber filler components. I won’t assert that current production of the same colour will have the same effect, but it’s something to be aware of. I also think it may have been a particular problem in that sort of filler, since the lubricated parts are immersed in the ink at all times; the more common piston filler (which Montblanc pens use) only presents the face of the piston seal to the ink, so there’s a reservoir of lubricant maintained on the sides. I want to underline that the fabric of the pen was not affected; however, in a pen that’s less user-serviceable than a TWSBI, this sort of behaviour could cause serious upset.