As I got back into fountain pens, my ink obsession got quickly out of control. I plan on sharing inks with friends and family, and wanted to be able to show them the color without having to ink up the pen. I'd seen a couple other pen bloggers out there who use the Maruman Word Cards, so I figured I'd jump on the bandwagon since I've yet to find anything else that didn't require me to hand cut larger sheet to keep them portable.
Funny enough, these cards are not meant for ink swabs despite how well they work for that purpose. They're actually designed for memorization. "Mnemosyne" is the personification of memory in Greek mythology. When you open up the Word Cards, the first card is a bright yellow stock that reads "Mnemosyne; The ancient Greek goddess of memory," along with some Japanese writing that I wish I were able to translate. From what I understand, kids in Asia have to memorize a lot of different language characters, so these are used extensively over there.
As far as the cards themselves, there are 100 cards on a ring which opens allowing you to move them around and organize as you wish. The paper is a watercolor stock that is toothy and not smooth, and is fairly thick. Surprisingly, despite the thickness, the whole ring of cards weighs next to nothing. I was actually surprised to see how big they were when I received them. The pictures online would have you thinking they are a lot smaller -- in my head I thought they would be about 50% larger than the keychain reward cards that you keep on your keys; but they are in fact about 4"x2". They really are the perfect size for ink swabs.
The ink on these is pretty close to its color on regular paper. It tends to be a tiny bit duller than ink would appear on a Rhodia or Clairefontaine page as they're a bit more absorbent. Though, for my purposes - and likely most ink catalogers - they are just fine.
Maruman makes a lot of other paper products that play well with fountain pens. I'm liking these so far for a quick glance to show someone an ink color, or to look back for my own reference, so I definitely recommend them. I picked mine up for $4.45 on JetPens.