Uniball Signo UM-151 Gel Pen Review

Waterproof but not smudge proof?
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I wish this pen didn’t smudge!

There are so many things to love about the Uni-ball Signo UM-151 gel pen. In fact, I’ve been using it lately and really do love it. But there’s one major drawback that bugs me… the smudging. Now, don’t get me wrong, it’s now a huge problem because I don’t normally drag my hand through the ink I just laid down, but if you’re a lefty, this would definitely be a problem. 

However, I was shocked when I did the smudge test – the results were quite interesting. The highlighter test didn’t fair well and all the highlighters I used resulted in smudging. The water test happened on a different day (I think it was 3 days later) and there was absolutely no smudging or smearing when I ran a wet paintbrush across the written word. Whoa! I hadn’t expected that. 

But as I’m writing this I started to grow skeptical (of course!) so I did another water test. I waited 30 seconds for the ink to dry and then ran a wet paintbrush over the words. Oops! Smearing like crazy! So I guess the lesson here is that the ink is waterproof but you have to wait a couple of days. Which is fine if you want your writing preserved and safe for future generations (or for your notebooks to survive floods). But if you’re an art journaler and need to add watercolor or other mixed media on top of your written word… you’re outta luck. 

The writing is SMOOTH and the ink saturation is nice and dark – exactly what I want in a pen. Plus, it’s a pen with a cap – which is my personal preference. Normally I’m annoyed with finger grips but for some reason, I’m not bothered by this one. Maybe because it fits nicely in my elastic pen loop better than a retractable pen with a finger grip does?

So many tip sizes (and colors) for the Signo!

If you’re someone (like me) who loves a super fine tip on a pen, this one is for you. I have tested the .38mm but there’s also a .25mm option if you want to go even smaller. But if you like things a bit fatter, you’ve got the .5mm size, also. And let’s not forget the amazing array of vivid colors. There are 31 color options and I love how saturated each one of the colors is. That’s all because of the pigmented gel ink which gives us lots of color options. I also love that they’ve named the colors AND include that name right on the pen itself. (See the full list below.)

What’s the difference between Uniball Signo UM-151 and Signo DX?

It took me some digging to finally realize that the two different names are actually the same pen. In Japan, it’s referred to as Signo DX but in the rest of the world, it’s the Signo UM-151. (Thanks JetPens for enlightening me on that!) It’s important to know this info just in case you come across a super great bargain from a Japanese pen seller, right?!

Stationery Nerd (only 90%) Approved

Overall, I love this pen! It’s a great choice if you’re looking for a super smooth writing experience in a lightweight pen. I think you’re going to love it too. I’m reserving the full-blown Stationery Nerd Approval rating because of the smudging issue. But if you take out the smudging issue, this pen is perfect. So it’s getting a 90% Approval Rating. 

I’ve listed all the other specs for this pen below.  But if you have questions on anything I might have missed, hit me up in the comments below and we can chat about it. Do you love this pen? How many of the 31 colors do you have? (I only have 19 but I’m thinking the rest of the set is going on my shopping list!)

 

Pen Specifications

  • Ink – water-based pigmented gel ink
  • Water Resist/Proof – yes, after 24 hours. Not immediately.
  • Waterproof Test – Applying water after 30 seconds gives major smudging. But after 24 hours, no smudging and becomes totally waterproof.
  • Tip Size –  .28mm  | .38mm  | .5mm
  • Structure – stick pen with cap
  • Clip Style – plastic clip on cap
  • Finger Grip – dimpled rubber
  • Construction – plastic body with a metal head
  • Finger Smudge Test – 8 seconds dry-time to no-smudge
  • Highlighter Test – smudges with all tested
  • Refillable – yes  | UMR-1
  • Color Options – 31 colors total

Uni-Ball Signo UM-151 (DX) Color Options:

  • Red
  • Baby Pink
  • Pure Pink
  • Pink
  • Light Pink
  • Bordeaux Black
  • Mandarin Orange
  • Orange
  • Golden Yellow
  • Yellow
  • Apple Green
  • Lime Green
  • Green
  • Emerald
  • Green Black
  • Blue Green
  • Sky Blue
  • Light Blue
  • Blue
  • Prussian Blue
  • Blue Black
  • Purple 1
  • Purple 2
  • Lilac
  • Brown
  • Khaki
  • Beige
  • Brown Black
  • Dark Gray
  • Gray
  • Black

Uni-Ball Signo UM-151 (DX) Pen Photo Gallery

Click on an image below to enlarge it …. so you, too, can inspect the greatness of this pen!