I was unable to get the desired result from this following the video, and i could not get the black to become transparent. But after some fiddling i got it to work,and i don’t know if its because i use 2.78b or not, but maybe i missed a step with your setup?
Except, my grass is a little more white, than green now. This is where im stuck hah.
Upon more playing, It shows that its transparent in the “Preview” but not in the Material/Object? But when i render it, it shows transparent? What am i doing wrong here?
I also had that, played around with a few settings and eventually reloaded the image - then it came good. No idea why it did this. The image definitely has an alpha channel.