Pen-Opake vs. all other white inks

Pen-Opake is the best white ink there is. The only problem is that they stopped manufacturing it several years ago and nobody seems to have a stash for sale. Occasionally it is mentioned nostalgicly on some art blog or another, but other than there is little info about it on the net or anywhere.

I've been using up the few crusty bottles I procured from the Junk Store on all those ink-and-white-on-paper-bag drawings I've been doing, so I set out to find a suitable replacement. Some illustrator friends of mine mentioned that FW Acrylic Ink is a very opaque and fluid white, so I procured me some and put it to the test... a test it failed miserably.

So I went through my stash of white inks and gouaches to see who had what it takes.

I tested the FW, Rotring, Talens Ecoline, Pro White, Pen-Opake, and Higgins Super White, all in jars with a brush on a paper bag. I also tried tubes of Talens Plakkaatuerf, Winson & Newton Designers in both Permanent and Zinc White. Some of the thicker ones needed a touch of water to get going.The Pen-Opake was easily the best and brightest. And this was from a jar that is likely 20 years old. The Talens Ecoline was a decent 2nd place, and I suppose the Pro-White will do in  a pinch. The Rotring and FW are liquid, which I thought would work well in a japanese water-brush, but I thought wrong. The Higgins was, by far, the worst.All the tubes of gouache looked pretty good. I was hoping to find a suitable replacement for Pen-Opake that is bright and opaque but fluid enough to use in the water-brush. I also ended up learning quite a bit about water-brush technology and the fact that my current white brush only works because it is a cheap imitation without a stopper mechanism to block the overflow of water. Fascinating.So, yeah, if you come across any Pen-Opake in any condition, let me know and I'll buy it from you. Or if you have any other bright ideas about an opaque white, hit me up.
The water-brush jar.