I wound up printing this job with Matsui Spot Black, with 3% Fixer N and 3% Printgen MG added.
I decided to sacrifice a garment, but I wasn't supposed to. I'm sure glad I did, because my first test wash failed with the WB ink. I decided to try a plastisol transfer (One Stroke Kit) and it was perfect...but it puckered a little after dryer during the test wash, and I didnt care much for the"hand" on this particular garment.
So I went back to the Matsui Spot Black.
I figured perhaps my first attempt with WB might have been undercured, and it turned out I was right. I'm running a modded infrared Harco with only 6 feet of heat...but with BIG AIR upgrades on my WB and WB Discharge Jobs. BUT.....I also start the curing process with a pretty hard flash in head 3, and another flash in 6 if I can. I was afraid to do steaming HOTT flashes with 95% Rayon. That's why my FIRST Matsui test print failed. I've never had a WB job fail a wash test before, but now I know what it looks like, and that is a good thing.
Kind of amazing, that in almost 4 years of curing WB in an infrared that I'd never seen WB fail a wash test before, but I didn't get an auto until a year ago. I just never pushed my dryer to the point of failure, I guess. (Cudos to Winston, for all the help tweaking my drier!)
Anyway, the first wash DOES degrade the Black's "pop" just a skoshe, but I went ahead and ran the Job with Matsui. The only degradation occurred after wash cycle #1 and after that I'd consider the print quite solid.
And on cotton, properly cured Matsui Spot Black with Fixer N and Printed MG produces THE BLACKEST, most durable prints we've ever done, period. Near ZERO fibrillation after multiple test washes. Wonderful prints, zero hand. Plastisol can't hold a candle to it for fibers and feel! But a thousand prints is about all I can get out of my WR 25 before I need to be thinking about screens. I'll have to work on that.