Waterman Fountain Pen Ink (Mysterious Blue) 50ml Bottle

What this ink is for

Waterman’s fountain pen ink in Mysterious Blue is a liquid dye designed for use in fountain pens, aiming to deliver bold, noticeable lines. If you like your writing to stand out on the page, this one is pitched around intense colour rather than subtle shading.

On paper, it’s the sort of bottle you keep on hand for everyday refills: the idea is simple—add ink, keep writing, and avoid the hassle of short-lived, colour-bleached bottles. The “mysterious” part is more about the name and look of the blue tone than anything you can measure, but the intent is clear: readable ink that doesn’t disappear into the paper.

It also comes in a 50ml glass bottle with faceted styling and a screw cap. That matters more than you’d think if you refill often, because a secure closure and straightforward handling tend to make the process less messy.

The essentials: what stands out

Where this ink feels most compelling is its focus on line intensity and overall writing comfort. The description specifically points to “intense lines” and a formula meant to improve performance and make writing more comfortable.

That’s a sensible direction for anyone who: - writes regularly and wants consistent colour impact, - prefers a well-behaved ink experience rather than something that feels dry or inconsistent, - wants a reliable bottle for routine top-ups.

That said, no ink is perfect for every pen and every paper. If you’re particularly sensitive to wetness, paper bleed, or shading behaviour, you may want to be cautious—especially because those outcomes depend a lot on your pen’s nib/feed and the paper you use.

Usage tips for refills

For most people, the practical challenge isn’t “what ink is”, it’s “how do I avoid mistakes when refilling?”. With this bottle’s screw cap and glass body, it’s built around easy handling.

A simple, low-stress routine looks like this: first, make sure your pen is ready for a refill (for example, if you’re switching colours, empty the existing ink), then open the screw cap and add the ink carefully without rushing. Faceted glass can be a nice grip aid, but still keep control of the flow—fountain pen ink can spread quickly if you’re not neat.

Compatibility and what to double-check

The product description states it is compatible with all Waterman fountain pens. That’s helpful if you already stay within the Waterman ecosystem, because it removes a big chunk of guesswork.

Still, there are two things worth checking before you commit: 1) your pen’s ink requirements (for instance, if your pen is sensitive to flow or has a particular preference), 2) how the ink behaves on your everyday paper.

If you’re using it in a fountain pen outside the Waterman range, the description doesn’t promise compatibility—so it’s better to be cautious and confirm with the pen’s guidance first.

Where it fits best (and where it may not)

This is a good match if you want a dependable bottle of blue ink that produces clear, intense lines and is designed to feel comfortable to write with. It also suits anyone who refills from a bottle and prefers a cap that’s easy to close securely.

It may not be the best choice if: - you need a very light, discreet blue for subtle writing, - you use very absorbent paper and you’re worried about bleed or feathering (no claim is made here about paper performance), - you only write occasionally and want something you’ll use up fast.

Mini FAQ

Is Mysterious Blue more of a dark or light blue?

The description emphasises “intense lines” and an eye-catching blue tone, so it’s intended to look bold rather than washed out. Exact shade depth on your paper can vary, though.

How much ink is in the bottle?

The bottle is 50ml.

Is it easy to open and close?

It uses a screw cap on a faceted glass bottle, which is generally the kind of design that makes refilling less fiddly.

Will it work in any fountain pen?

The description says compatibility with all Waterman fountain pens. For other brands, it doesn’t provide a guarantee.

Should you store it carefully?

Any ink is best stored upright with the cap secured, and the screw-top design is there to make that practical.

Final verdict

It makes sense if you own a Waterman fountain pen and you want a straightforward bottle of Mysterious Blue ink that’s designed for intense, standout lines and comfortable writing. It’s also a practical refill choice thanks to the 50ml size and screw-cap glass bottle.

You may want to skip it if you’re using a non-Waterman pen and need confirmed compatibility, or if your priority is a very subtle blue that stays discreet on tricky paper. If you’re buying for general daily use on normal paper and you want the colour to show, this one is a sensible buy to keep in your drawer.