(Susan M. Pigott is a fountain pen collector, pen and paperholic, photographer, and professor. You can find more from Susan on her blog Scribalishess.)
The Midori Color Paper Notebook is a 28-sheet (56 pages front and back) staple-bound, soft-cover notebook in A5 (8x6 inches). The series, which comes in several colors, including pink, blue-green, purple, yellow, brown, and yellow-green, is meant to evoke French macaron's, with darker colors on the outside and softer colors on the inside.
Each notebook has an oval heading area on the cover outlined in gold (this shape is based on the macaron). The pages inside are lined in gray ink with 6.5mm spacing. The paper weight is not indicated on the notebook, the JetPens website, or the Midori website, but it is heavy enough to handle fountain pens (see below).
The notebook offers plenty of lines per page for writing substantial thoughts, but it is small enough to fit in a larger notebook or a purse. These notebooks stand out from other Midori notebooks because of their bright covers and pastel interiors. They are well made, but they won't hold up to heavy abuse. The card stock cover is fairly light and bends easily. Pages are not perforated so if you want to remove one, you'll have to tear it out carefully. The notebook does not lie flat on its own, though you could probably bend the cover backwards to help it stay open.
The paper holds up well to different pens and inks. I tested it with most of my fountain pens, each with a different color of ink, as well as a few other kinds of pens.
Although in my first test, the Pelikan Jade ink in my Omas bled and feathered, I think this is because I had just refilled the pen.
When I re-tested that particular ink and pen, the paper handled it fine.
Even my broadest, wettest nib (a Nakaya music nib inked with Sailor Yama-Dori) did not bleed through or feather.
There was, however, some show-through with several of the inks. Thus, if you plan on using fountain pens, you might want to use only one side of the pages, which means you'll only get 28 pages per notebook.
Although the Midori Color Notebook is nicely made, it is not something I would likely use. For journaling, I prefer notebooks with more pages that can be put in a refillable cover. For people who like to have multiple notebooks for different tasks, however, these might be quite useful. For example, a student could use a different color notebook for each class (though he/she wouldn't be able to take copious notes). A person who keeps a gratitude journal could use a different color each month and rotate them. They would make beautiful guest books for baby or bridal showers. I suspect these notebooks will be popular with many people.