The majority of people who tint their canopies do it using RIT Dye. They heat up water and dissolve a couple of packs and submerge the canopy. I've never done it myself but there are plenty of posts here in RCU which cover the subject thoroughly. It always seems that the color of the dye will result in a different color on the canopy when the job is done. Its recommended to experiment on a spare piece of the canopy's plastic to make sure it tints just the right shade you're looking for. You have to be very careful with the water's temperature because it can warp the canopy and render it useless.