Penetralia ~ Fountain pen review ~ Monteverde Innova 20th Anniversary Rainbow LE

I got this pen around the middle of 2021 and definitely felt there was a moment where rainbow pens were everywhere! My first rainbow pen was the TWSBI Vac700r — Iris and then suddenly I noticed them more! This came across my radar and I needed it to build up my rainbow pen collection. DuH!

There are many reviews for this pen elsewhere, it’s a newish pen and a revival of a classic. I’m not going to spend a lot of text going over measurements etc. I want to give you my personal thoughts.

In this review, I’ll go over my favourite features of this pen and what I don’t like. I’ll picture some writing samples with different inks, to give you a feel for how it handles various types of ink. In summary, I’ll discuss why this pen is in my collection and whether this pen is truly worthy of being a GP’s pen!

My stunning black stub nib


Let’s start with the obvious. The body. This is a carbon fibre pen and it’s truly stunning. I’m a huge sucker for having pens of various materials in my collection. I’m already little bored of “just” acrylic pens everywhere — topic for another day. Yes, I’m primarily a nib collector, but add on a nice pen body and it’s almost a sure purchase from me. I have a wooden pen now, my brass Kaweco sport and soon to add some Urushi pens too.

This carbon fibre rainbow pen is a must! I do not know why it’s a rainbow pen and I have no interest in making any political nods to any political groups just based on a few colours on a pen. I honestly enjoy this pen purely for it’s design and colour choices — as is true for all my rainbow pens. The cross hatching looks fantastic and adds depth to the pen body, reflects light beautifully and keeps the eye pleased as one writes. The rainbow trim, clip, finials, just add the perfect POP in just the right places to add highlights. Comparing this to my Conklin Matte black/rainbow pen, this pen is the Joker whereas the Conklin is Batman!

The pen came with a limited edition black ink, which I have no intention of using. I have too much ink as it is, and this teeny tiny bottle is the bottom of my priorities.

I have to say, after a tiny bit of tweaking, the Jowo stub I have on mine is brilliant! It’s one of two stubs I have and I really enjoy them both. The writing experience is fantastic, with the right ink it glides quite nicely and on some paper (eg Midori MD) it’ll squeak on the page for you! I’m glad they went for the black finish on the nib as any other would have looked stupid. It’s a cartridge converter (which is my favourite filling system) so combined with this huge wet nib, I get through my ink pretty quick, which is great!

I love the snap cap design too. It’s ready for action whenever you are and the pen never dries out, even after it’s been sitting in my pen case for like a month unused. It even snaps onto post.

Oh and it’s a numbered limited Edition! TAKE MY MONEY!


For my liking it’s a little light, but that’s NOT a big deal and slightly back-weighted when posted, but I rarely post my pens so again, no big deal.

Gosh, honestly I can’t think of anything else I don’t like about this pen!

Writing Samples

Left: 90gsm copy paper. Right: Clairefontaine 90gsm paper.
Left: Clairefontaine 90gsm paper; Right: 90gsm copy paper

I apologise for my horrendous writing sample images, but this pen makes ink look awesome! A thick juicy nib lays down so much ink that ANY ink properties glare off the page monstrously. Shimmer is visible from across a car park and the sheen from the organic studios ink makes it look like I’m writing with an oil spill off tarmac! It’s amazing! Definitely a great pen to experiment with inks. As you can see it also makes my handwriting very different to usual, dare I say, slightly more artistic!

There’s no way in hell you’re getting a thinner line if you rotate this stub nib. Also the sweet spot for this nib is fairly precise. Nor does this nib handle fast writing and signatures well.

OOOOO the shimmer and sheen!

Why is this pen in my collection?

There’s a lot here to enjoy. It looks great. It’s shiny and mad and has lots of great qualities I look for in a pen. I really enjoy the variety it gives my nib collection — not “just” another Jowo6 nib — topic for another day.

If you’ve read my other entries, you’ll know I like limited editions — I’m a total sucker for the marketing! So, of course I’m very happy I snagged this when I could. For the price, this is a brilliant addition to anyone’s collection.

Is this a pen fit for a GP?


Its easy to clean, the cartridge convertor and the snap cap is very convenient. It’s very quick to open and the clip not only looks great but functions very well. The “S” design grabs your shirt/pocket very easily and this pen isn’t going to fall off your shirt or rip your pocket getting it.

This is a great pen body for a doctor on the move or at your desk. It’s visible enough that if you put it down, you’re going to notice and not lose it. It’s not so expensive that it’ll attracts thieves, and even if it did, it’s not a massive investment lost. If you pair it with a funky shirt or you’re like me with a bit of an extrovert personality, it’ll pair nicely with you and your style.


It doesn’t exactly scream, “serious Doctor” at work! meh… I don’t really care about this. My patient know me well enough to know I’m a bit quirky. Even in the hospital setting, the doctor with the mad shirt, odd socks and “sleeve holders” gets away with it.

I definitely picked the wrong nib size for work - I cannot write with this nib AT ALL. I can’t do forms, I can’t sign prescriptions (etc) and I can’t write in paper notes. It’s not great at fast writing — so no good for ward rounds and doing signatures — and has a smaller “sweet spot” — so no writing at funny angles whilst carrying 15sets of paper files as you rush around a ward round. This is a nib made for slow careful writing, it mostly stays as a journaling pen for me. It can’t do forms with tiny little boxes to fill out, and the ink flow means it feathers all over the damn place on crap paper.

Definitely, get this with a medium or fine nib. The pen itself is great — for this reason, I basically consider this pen yet another “jowo stick”, if I really wanted to use it more at work I’d swap out the nib for another black Jowo.

I’d highly recommend this pen, with the right nib size for it’s intended use. It’s now one of four rainbow pens I have (just need one more to fill my Shibui case!)

Thanks so much for reading and remember no matter who you are, “first, do no harm.”




An Australian GP with a love for fountain pens, writing, gaming and gardening, throwing in an occasional rant along the way!

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An Australian GP with a love for fountain pens, writing, gaming and gardening, throwing in an occasional rant along the way!

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