Here’s a possible media combination, and the technology involves color and human perception. We want the different particle sizes to be recognizable. Color works, but our colors are limited, and video introduces more complexity.
And they look different when they’re wet, and we put dye in the water. That’s another variable, good grief.
Here’s a combination we’re looking at, with a greyscale stripe across the middle. Can you distinguish the red from orange? The blue from the brown? Notice how the white isn’t really white. We need to be concerned about how the human eye sees these, and also how video chips do.
We’ve worked for years to get a supplier to custom grind this stuff for us. We need around 500 pounds of media for an Em4, and this stuff isn’t cheap.