It depends on the brand of sheets you have. I know icingimages sheets are very easy to work with but others can be brittle, tear and are hard to remove from the backing. You'll just have to experiment with the sheets you have and see what works.
If you want red or black instantly use chefmaster liqua gel colors. Highly concentrated, use very little, no bitter taste and doesn't need to be made a day ahead. Just do a google search for a supplier.
I also use a canon but I prefer the premium frosting sheets and gold label inks from icingimages. I've tried the other brands and these sheets release from the backing so much easier. Their inks also seem to be more vivid.