(Susan M. Pigott is a fountain pen collector, pen and paperholic, photographer, and professor. You can find more from Susan on her blog Scribalishess.)
Montblanc "Blue Hour" or "Twilight" is "linked to the 'blue hour,' the time when the day turns to night," according to Montblanc's website. The ink comes in a 30ml square glass bottle adorned with the Montblanc emblem on the cap. It is a limited edition ink.
When I first saw a sample of this ink, I couldn't wait to purchase a bottle. It looked lovely with deep blue-green tones, sheen, and shading. I love blue inks, and I expected great things from Montblanc Blue Hour.
But when I inked my first pen with Blue Hour, I was disappointed. The ink didn't have the depth I was expecting. Where was the sheen? Where was the shading? And, worst of all, after I wrote a few pages and the ink dried, it faded to a sort of dusty bluish-green. You can see in the picture below how the ink is deep blue when it's fresh and dusty blue-green when it has dried.
I tried it in several different pens with various nib sizes and grew more disappointed. Broad nibs bring out the shading, but the ink was dry and unsaturated in my finer nibs.
The only way I was able to get sheen from the ink was in droplets. None of my writing samples, even with my super broad, flexible music nib, exhibited any sheen.
Chromatography demonstrates that the ink has blue, green, and yellow tones. I expected it to be more of a blue-black, but it leans more towards teal.
Blue Hour is not a wet, highly-saturated ink. When you do a smear test, it dries quickly. Obviously, the dry times will be longer with broader nibs, but not by much. The ink is not waterproof.
When I first used Blue Hour, I thought it resembled Iroshizuku Tsuki-Yo. The two inks look similar, but Tsuki-Yo has more green and the color definitely doesn't fade. Tsuki-Yo also flows better, especially in fine nibs.
I'm glad Blue Hour came in the smaller 30ml bottle, because this is not an ink I will use much. After falling in love with Montblanc Toffee, I genuinely thought this would be a terrific ink. But it is dry; it fades, and it simply fails to impress.