If you shine a red light at night on a freshly sprayed field (as in hours before) the sprayed grass will appear black. The unsprayed looks much more gray/green. I sprayed a small spot with glypho and then hunted it hours later for predators and noticed the obvious color difference.

What use this has in real life.... no idea other than I saw a spot I missed and now weeks later it is confirmed I missed it.

As you were.

Folks being using IR photography for detecting soil health for years.

I think it was also used in Vietnam to detect the difference in live and dead foliage. Recently cut foliage to camo tanks and other things were easily detected with IR photos.

^^ Cool, I guess visible red light is close enough to IR to do some of the same things.

My guess would be its the surfactant that is making it appear black.

There is a dye that you can put in a sprayer to show you where you are and what you miss. It comes in red or green color and will dissipate in a few days

Also in blue

That dye is like handling a grease gun in your Sunday clothes. Just look at it and it jumps all over me...lol

Yep. If I'm trying to keep it off of me, I'll look down and it's on me head to toe. If I don't worry about getting it on me, old clothes, old shoes, rubber gloves....I'm clean as a whistle.

You aren't kidding. I can wipe the bottle down, it be completely dry, and then add some to the tank, and I got it all over my fingers.

No doubt. I can never use that stuff without getting it on my hands and clothes no matter how careful I am.