Can light weight canvas on shade canopies be painted?

Yes.. that's is what artists use to paint on...canvas.

Might be able to dye too

Yes, but you should apply a coat of purchased or homemade Gesso first. Use acrylic artist or latex house paint. Hint: you can mix acrylic Artist paint in latex paint to mix colors.

however, if you fold the shade a lot, the paint may crack, so you may want to consider dye or inks (sharpies work).

I've used fabrics markers on one before

Carolyn is correct about the paint on canvas cracking. Painted canvas will last a long time in the weather but should ENT be folded

CONTINUATION: Painted canvas shouldn’t be folded. Although paint will be more vibrant, dye will allow the fabric to still be flexible. A thinned out wash of a latex paint may do the same thing. Get a small canvas drop cloth from the paint store to test several methods.

Yes. It will fade in the sun. I have used spray paint, acrylic paint, fabric markers and Sharpies. All have done well, but they did fade and the paint will crack over time and if folded

Yes. I did it on a curtain, looks good, but is inside. Used regular paint

Some acrylic paints can be mixed with a fabric medium then applied to any type of fabric. It can also be diluted with water and sprayed onto fabric. This doesn't make the color lighter in my experience, but does allow it soak into the fabric rather than sit on the surface. There are other paints specifically for fabric, but may not be available in such a large quantity as you need.

Fabric dyes are perhaps a better choice, but you would need a very large container to mix the soda ash in and soak the fabric, and later to dye the fabric. Take a look at Dharma Trading Company for a large selection of dyes and paints for all types of fabrics.