I dyed my canopy with Rit dye using the following procedure:

Approximately 2 gallons of water
One cup of Salt
2 packages of Black Rit Dye and One package of Denim Blue
Tap water at 130 degrees
Cleaned the canopy with dish washing soap twice and handled it only by the edges
Let soak in dye solution for 60 Minutes.
I kept the solution hot by surrounding the container with 130 degree hot water. I got a very slight curl on one edge so Next time I will use 130 degree water but let it cool naturally.

The canopy came out a very deep black/amber that looks black to the eye.